Fix unbound variable error in gce/configure.sh
Fix unbound variable error in gce/configure.sh

Looks like UBUNTU_INSTALL_RUNC_VERSION should be optional here.
kubernetes/kubernetes,fgimenez/kubernetes,mosoft521/kubernetes,cofyc/kubernetes,jackfrancis/kubernetes,cblecker/kubernetes,GulajavaMinistudio/kubernetes,dixudx/kubernetes,x13n/kubernetes,kpgriffith/kubernetes,xlgao-zju/kubernetes,deads2k/kubernetes,rafax/kubernetes,Clarifai/kubernetes,jdef/kubernetes,micahhausler/kubernetes,xychu/kubernetes,erwinvaneyk/kubernetes,enj/kubernetes,sanjeevm0/kubernetes,JacobTanenbaum/kubernetes,nak3/kubernetes,openshift/kubernetes,li-ang/kubernetes,joelsmith/kubernetes,fejta/kubernetes,tallclair/kubernetes,k82/kubernetes,tomzhang/kubernetes,kpgriffith/kubernetes,ravisantoshgudimetla/kubernetes,k82cn/kubernetes,jagosan/kubernetes,thockin/kubernetes,pires/kubernetes,cblecker/kubernetes,chestack/kubernetes,tengqm/kubernetes,matthyx/kubernetes,kubernetes/kubernetes,idvoretskyi/kubernetes,deads2k/kubernetes,zetaab/kubernetes,chrislovecnm/kubernetes,joelsmith/kubernetes,andrewrynhard/kubernetes,joelsmith/kubernetes,tpepper/kubernetes,GulajavaMinistudio/kubernetes,dereknex/kubernetes,mfojtik/kubernetes,zhangmingld/kubernetes,openshift/kubernetes,erwinvaneyk/kubernetes,MikeSpreitzer/kubernetes,dlorenc/kubernetes,huangjiuyuan/kubernetes,tpepper/kubernetes,ixdy/kubernetes,yarntime/kubernetes,fanzhangio/kubernetes,wanghaoran1988/kubernetes,ravilr/kubernetes,fgimenez/kubernetes,PI-Victor/kubernetes,zhouhaibing089/kubernetes,dims/kubernetes,humblec/kubernetes,warmchang/kubernetes,kitt1987/kubernetes,carlory/kubernetes,mahak/kubernetes,spzala/kubernetes,liggitt/kubernetes,mboersma/kubernetes,xychu/kubernetes,zhangmingld/kubernetes,olivierlemasle/kubernetes,chestack/kubernetes,kpgriffith/kubernetes,Lion-Wei/kubernetes,iterion/kubernetes,tengqm/kubernetes,ping035627/kubernetes,lojies/kubernetes,humblec/kubernetes,spzala/kubernetes,yujuhong/kubernetes,weiwei04/kubernetes,verb/kubernetes,humblec/kubernetes,openshift/kubernetes,dlorenc/kubernetes,huangjiuyuan/kubernetes,tpepper/kubernetes,sethpollack/kubernetes,roberthbailey/kubernetes,tomzhang/kubernetes,alejandroEsc/kubernetes,zetaab/kubernetes,feiskyer/kubernetes,krmayankk/kubernetes,krmayankk/kubernetes,enj/kubernetes,chestack/kubernetes,dlorenc/kubernetes,PI-Victor/kubernetes,kpgriffith/kubernetes,fejta/kubernetes,joelsmith/kubernetes,liggitt/kubernetes,jackfrancis/kubernetes,yarntime/kubernetes,coolsvap/kubernetes,jdef/kubernetes,sanjeevm0/kubernetes,fgimenez/kubernetes,cmluciano/kubernetes,du2016/kubernetes,nckturner/kubernetes,hex108/kubernetes,PI-Victor/kubernetes,johscheuer/kubernetes,olivierlemasle/kubernetes,x13n/kubernetes,mboersma/kubernetes,gnufied/kubernetes,mfojtik/kubernetes,tcnghia/kubernetes,iterion/kubernetes,wongma7/kubernetes,iameli/kubernetes,fabriziopandini/kubernetes,wanghaoran1988/kubernetes,verb/kubernetes,PI-Victor/kubernetes,bparees/kubernetes,ravisantoshgudimetla/kubernetes,rnaveiras/kubernetes,dims/kubernetes,tcnghia/kubernetes,fanzhangio/kubernetes,aledbf/kubernetes,BenTheElder/kubernetes,li-ang/kubernetes,andrewrynhard/kubernetes,mYmNeo/kubernetes,thockin/kubernetes,klaus1982/kubernetes,stevesloka/kubernetes,tomzhang/kubernetes,monopole/kubernetes,fejta/kubernetes,johscheuer/kubernetes,fanzhangio/kubernetes,JacobTanenbaum/kubernetes,fabriziopandini/kubernetes,aledbf/kubernetes,PiotrProkop/kubernetes,Lion-Wei/kubernetes,stevesloka/kubernetes,mkumatag/kubernetes,nikhita/kubernetes,tallclair/kubernetes,csrwng/kubernetes,JacobTanenbaum/kubernetes,maciaszczykm/kubernetes,zhouhaibing089/kubernetes,tcnghia/kubernetes,kubernetes/kubernetes,nckturner/kubernetes,ravilr/kubernetes,hex108/kubernetes,rnaveiras/kubernetes,krmayankk/kubernetes,jackfrancis/kubernetes,roberthbailey/kubernetes,chrislovecnm/kubernetes,aledbf/kubernetes,andrewsykim/kubernetes,cblecker/kubernetes,aledbf/kubernetes,gnufied/kubernetes,enj/kubernetes,xlgao-zju/kubernetes,MHBauer/kubernetes,ixdy/kubernetes,jessfraz/kubernetes,iameli/kubernetes,x13n/kubernetes,matthyx/kubernetes,jingxu97/kubernetes,monopole/kubernetes,dixudx/kubernetes,ixdy/kubernetes,Clarifai/kubernetes,stevesloka/kubernetes,MikeSpreitzer/kubernetes,kevensen/kubernetes,wanghaoran1988/kubernetes,mfojtik/kubernetes,rnaveiras/kubernetes,MHBauer/kubernetes,jingxu97/kubernetes,jessfraz/kubernetes,andrewsykim/kubernetes,shyamjvs/kubernetes,maciaszczykm/kubernetes,luxas/kubernetes,weiwei04/kubernetes,ravisantoshgudimetla/kubernetes,spzala/kubernetes,soltysh/kubernetes,du2016/kubernetes,spzala/kubernetes,wongma7/kubernetes,jsafrane/kubernetes,kitt1987/kubernetes,dims/kubernetes,xlgao-zju/kubernetes,andrewsykim/kubernetes,mikebrow/kubernetes,brendandburns/kubernetes,liggitt/kubernetes,JacobTanenbaum/kubernetes,kitt1987/kubernetes,li-ang/kubernetes,mkumatag/kubernetes,pwittrock/kubernetes,rnaveiras/kubernetes,JacobTanenbaum/kubernetes,kevensen/kubernetes,kitt1987/kubernetes,ping035627/kubernetes,tpepper/kubernetes,linux-on-ibm-z/kubernetes,erwinvaneyk/kubernetes,tallclair/kubernetes,dims/kubernetes,sdminonne/kubernetes,cmluciano/kubernetes,sdminonne/kubernetes,rnaveiras/kubernetes,gnufied/kubernetes,kevin-wangzefeng/kubernetes,nckturner/kubernetes,tallclair/kubernetes,kpgriffith/kubernetes,saad-ali/kubernetes,andrewsykim/kubernetes,cofyc/kubernetes,sdminonne/kubernetes,jessfraz/kubernetes,krmayankk/kubernetes,ravisantoshgudimetla/kubernetes,zetaab/kubernetes,lojies/kubernetes,PiotrProkop/kubernetes,sanjeevm0/kubernetes,tomzhang/kubernetes,jsafrane/kubernetes,GulajavaMinistudio/kubernetes,wanghaoran1988/kubernetes,mboersma/kubernetes,johscheuer/kubernetes,fejta/kubernetes,maciaszczykm/kubernetes,mikedanese/kubernetes,chrislovecnm/kubernetes,feiskyer/kubernetes,cofyc/kubernetes,jsafrane/kubernetes,yarntime/kubernetes,liggitt/kubernetes,nak3/kubernetes,MHBauer/kubernetes,wongma7/kubernetes,nak3/kubernetes,brendandburns/kubernetes,tomerf/kubernetes,weiwei04/kubernetes,ingvagabund/kubernetes,zhangmingld/kubernetes,chestack/kubernetes,tallclair/kubernetes,rrati/kubernetes,rrati/kubernetes,dixudx/kubernetes,bparees/kubernetes,BenTheElder/kubernetes,Acidburn0zzz/kubernetes,stevesloka/kubernetes,jackfrancis/kubernetes,jdef/kubernetes,stevesloka/kubernetes,Lion-Wei/kubernetes,dixudx/kubernetes,yujuhong/kubernetes,mboersma/kubernetes,PI-Victor/kubernetes,fanzhangio/kubernetes,maciaszczykm/kubernetes,MHBauer/kubernetes,sanjeevm0/kubernetes,du2016/kubernetes,dlorenc/kubernetes,idvoretskyi/kubernetes,jingxu97/kubernetes,pwittrock/kubernetes,alejandroEsc/kubernetes,MHBauer/kubernetes,saad-ali/kubernetes,rafax/kubernetes,k82/kubernetes,thockin/kubernetes,mikebrow/kubernetes,yarntime/kubernetes,mosoft521/kubernetes,ii/kubernetes,nckturner/kubernetes,chrislovecnm/kubernetes,zhouhaibing089/kubernetes,nckturner/kubernetes,MikeSpreitzer/kubernetes,iterion/kubernetes,xychu/kubernetes,mikedanese/kubernetes,humblec/kubernetes,hex108/kubernetes,verb/kubernetes,lojies/kubernetes,cofyc/kubernetes,micahhausler/kubernetes,tomerf/kubernetes,weiwei04/kubernetes,jsafrane/kubernetes,ping035627/kubernetes,fgimenez/kubernetes,rrati/kubernetes,erwinvaneyk/kubernetes,jagosan/kubernetes,mengqiy/kubernetes,openshift/kubernetes,nikhita/kubernetes,nikhita/kubernetes,coolsvap/kubernetes,tomerf/kubernetes,ping035627/kubernetes,tomzhang/kubernetes,tomzhang/kubernetes,yujuhong/kubernetes,kubernetes/kubernetes,jessfraz/kubernetes,Acidburn0zzz/kubernetes,kevin-wangzefeng/kubernetes,feiskyer/kubernetes,mYmNeo/kubernetes,fejta/kubernetes,xlgao-zju/kubernetes,cblecker/kubernetes,PiotrProkop/kubernetes,kevensen/kubernetes,jagosan/kubernetes,zhouhaibing089/kubernetes,zhouhaibing089/kubernetes,carlory/kubernetes,warmchang/kubernetes,mosoft521/kubernetes,pwittrock/kubernetes,x13n/kubernetes,fanzhangio/kubernetes,kpgriffith/kubernetes,PI-Victor/kubernetes,nikhita/kubernetes,yujuhong/kubernetes,iameli/kubernetes,saad-ali/kubernetes,k82cn/kubernetes,pires/kubernetes,krmayankk/kubernetes,PiotrProkop/kubernetes,tpepper/kubernetes,dereknex/kubernetes,ii/kubernetes,nak3/kubernetes,Lion-Wei/kubernetes,sethpollack/kubernetes,rafax/kubernetes,ping035627/kubernetes,ingvagabund/kubernetes,fanzhangio/kubernetes,weiwei04/kubernetes,jagosan/kubernetes,cmluciano/kubernetes,verult/kubernetes,pires/kubernetes,mikedanese/kubernetes,roberthbailey/kubernetes,luxas/kubernetes,linux-on-ibm-z/kubernetes,mahak/kubernetes,jingxu97/kubernetes,pwittrock/kubernetes,warmchang/kubernetes,luxas/kubernetes,luxas/kubernetes,huangjiuyuan/kubernetes,andrewrynhard/kubernetes,mfojtik/kubernetes,xlgao-zju/kubernetes,yarntime/kubernetes,MikeSpreitzer/kubernetes,pires/kubernetes,PiotrProkop/kubernetes,zhangmingld/kubernetes,ixdy/kubernetes,du2016/kubernetes,ingvagabund/kubernetes,k82cn/kubernetes,mosoft521/kubernetes,li-ang/kubernetes,tomzhang/kubernetes,cmluciano/kubernetes,feiskyer/kubernetes,zetaab/kubernetes,csrwng/kubernetes,Acidburn0zzz/kubernetes,ingvagabund/kubernetes,monopole/kubernetes,joelsmith/kubernetes,mikedanese/kubernetes,mkumatag/kubernetes,zetaab/kubernetes,mengqiy/kubernetes,olivierlemasle/kubernetes,dixudx/kubernetes,huangjiuyuan/kubernetes,erwinvaneyk/kubernetes,tpepper/kubernetes,jingxu97/kubernetes,shyamjvs/kubernetes,xychu/kubernetes,xychu/kubernetes,dims/kubernetes,mikebrow/kubernetes,brendandburns/kubernetes,brendandburns/kubernetes,fabriziopandini/kubernetes,hex108/kubernetes,johscheuer/kubernetes,k82cn/kubernetes,sanjeevm0/kubernetes,sdminonne/kubernetes,saad-ali/kubernetes,tengqm/kubernetes,cofyc/kubernetes,soltysh/kubernetes,carlory/kubernetes,jdef/kubernetes,liggitt/kubernetes,cmluciano/kubernetes,mfojtik/kubernetes,erwinvaneyk/kubernetes,zetaab/kubernetes,shyamjvs/kubernetes,mengqiy/kubernetes,li-ang/kubernetes,dlorenc/kubernetes,tengqm/kubernetes,luxas/kubernetes,matthyx/kubernetes,csrwng/kubernetes,chestack/kubernetes,micahhausler/kubernetes,Clarifai/kubernetes,du2016/kubernetes,k82/kubernetes,klaus1982/kubernetes,deads2k/kubernetes,ravilr/kubernetes,k82/kubernetes,klaus1982/kubernetes,ixdy/kubernetes,lojies/kubernetes,weiwei04/kubernetes,nikhita/kubernetes,andrewrynhard/kubernetes,monopole/kubernetes,mikebrow/kubernetes,gnufied/kubernetes,dlorenc/kubernetes,mYmNeo/kubernetes,kubernetes/kubernetes,rrati/kubernetes,xlgao-zju/kubernetes,soltysh/kubernetes,saad-ali/kubernetes,yujuhong/kubernetes,coolsvap/kubernetes,sethpollack/kubernetes,nak3/kubernetes,sdminonne/kubernetes,ii/kubernetes,pwittrock/kubernetes,ravilr/kubernetes,shyamjvs/kubernetes,kevensen/kubernetes,mkumatag/kubernetes,ii/kubernetes,matthyx/kubernetes,spzala/kubernetes,ravisantoshgudimetla/kubernetes,wongma7/kubernetes,sanjeevm0/kubernetes,enj/kubernetes,jackfrancis/kubernetes,gnufied/kubernetes,alejandroEsc/kubernetes,dereknex/kubernetes,BenTheElder/kubernetes,rafax/kubernetes,thockin/kubernetes,idvoretskyi/kubernetes,carlory/kubernetes,rrati/kubernetes,dereknex/kubernetes,sethpollack/kubernetes,mboersma/kubernetes,carlory/kubernetes,Clarifai/kubernetes,bparees/kubernetes,mosoft521/kubernetes,maciaszczykm/kubernetes,fejta/kubernetes,bparees/kubernetes,MHBauer/kubernetes,jdef/kubernetes,lojies/kubernetes,ixdy/kubernetes,tcnghia/kubernetes,linux-on-ibm-z/kubernetes,k82/kubernetes,dereknex/kubernetes,johscheuer/kubernetes,tcnghia/kubernetes,iameli/kubernetes,iameli/kubernetes,verult/kubernetes,verult/kubernetes,feiskyer/kubernetes,luxas/kubernetes,wanghaoran1988/kubernetes,mengqiy/kubernetes,deads2k/kubernetes,mikedanese/kubernetes,mengqiy/kubernetes,BenTheElder/kubernetes,verult/kubernetes,pires/kubernetes,klaus1982/kubernetes,andrewrynhard/kubernetes,tcnghia/kubernetes,tallclair/kubernetes,dereknex/kubernetes,mahak/kubernetes,mYmNeo/kubernetes,ravilr/kubernetes,warmchang/kubernetes,yarntime/kubernetes,Acidburn0zzz/kubernetes,tomerf/kubernetes,mahak/kubernetes,jsafrane/kubernetes,mahak/kubernetes,kevensen/kubernetes,olivierlemasle/kubernetes,stevesloka/kubernetes,verult/kubernetes,MikeSpreitzer/kubernetes,kitt1987/kubernetes,shyamjvs/kubernetes,monopole/kubernetes,idvoretskyi/kubernetes,tengqm/kubernetes,mboersma/kubernetes,yujuhong/kubernetes,micahhausler/kubernetes,Lion-Wei/kubernetes,matthyx/kubernetes,pwittrock/kubernetes,mboersma/kubernetes,Clarifai/kubernetes,fabriziopandini/kubernetes,x13n/kubernetes,andrewrynhard/kubernetes,saad-ali/kubernetes,idvoretskyi/kubernetes,warmchang/kubernetes,csrwng/kubernetes,ii/kubernetes,tomerf/kubernetes,csrwng/kubernetes,alejandroEsc/kubernetes,chrislovecnm/kubernetes,iterion/kubernetes,k82cn/kubernetes,fabriziopandini/kubernetes,Lion-Wei/kubernetes,Acidburn0zzz/kubernetes,alejandroEsc/kubernetes,ravisantoshgudimetla/kubernetes,jessfraz/kubernetes,zhangmingld/kubernetes,wongma7/kubernetes,xychu/kubernetes,nak3/kubernetes,joelsmith/kubernetes,openshift/kubernetes,linux-on-ibm-z/kubernetes,Clarifai/kubernetes,huangjiuyuan/kubernetes,pires/kubernetes,verult/kubernetes,soltysh/kubernetes,verb/kubernetes,andrewsykim/kubernetes,mYmNeo/kubernetes,GulajavaMinistudio/kubernetes,iterion/kubernetes,tomzhang/kubernetes,ingvagabund/kubernetes,brendandburns/kubernetes,fgimenez/kubernetes,olivierlemasle/kubernetes,jagosan/kubernetes,hex108/kubernetes,cmluciano/kubernetes,sethpollack/kubernetes,ingvagabund/kubernetes,cofyc/kubernetes,mkumatag/kubernetes,mfojtik/kubernetes,huangjiuyuan/kubernetes,hex108/kubernetes,aledbf/kubernetes,krmayankk/kubernetes,roberthbailey/kubernetes,deads2k/kubernetes,fgimenez/kubernetes,kitt1987/kubernetes,mboersma/kubernetes,humblec/kubernetes,soltysh/kubernetes,jdef/kubernetes,johscheuer/kubernetes,mYmNeo/kubernetes,zhangmingld/kubernetes,coolsvap/kubernetes,mikebrow/kubernetes,JacobTanenbaum/kubernetes,coolsvap/kubernetes,Acidburn0zzz/kubernetes,roberthbailey/kubernetes,andrewsykim/kubernetes,tomzhang/kubernetes,kevin-wangzefeng/kubernetes,iterion/kubernetes,coolsvap/kubernetes,thockin/kubernetes,cblecker/kubernetes,bparees/kubernetes,verb/kubernetes,linux-on-ibm-z/kubernetes,idvoretskyi/kubernetes,BenTheElder/kubernetes,tomerf/kubernetes,brendandburns/kubernetes,x13n/kubernetes,kevin-wangzefeng/kubernetes,chrislovecnm/kubernetes,enj/kubernetes,maciaszczykm/kubernetes,GulajavaMinistudio/kubernetes,micahhausler/kubernetes,wanghaoran1988/kubernetes,kevin-wangzefeng/kubernetes