Fix panic in pkg/volume/csi tests
Fix panic in pkg/volume/csi tests

When run as non-root user, TestAttacherMountDevice fails, because of missing
nil check that induces a panic. Fixed by doing err nil check
before using the returned user value from user.Current()

weiwei04/kubernetes,openshift/kubernetes,jackfrancis/kubernetes,linux-on-ibm-z/kubernetes,rrati/kubernetes,BenTheElder/kubernetes,MikeSpreitzer/kubernetes,spzala/kubernetes,x13n/kubernetes,MikeSpreitzer/kubernetes,k82/kubernetes,micahhausler/kubernetes,PiotrProkop/kubernetes,nikhita/kubernetes,tengqm/kubernetes,jingxu97/kubernetes,deads2k/kubernetes,wongma7/kubernetes,tpepper/kubernetes,feiskyer/kubernetes,alejandroEsc/kubernetes,cofyc/kubernetes,jagosan/kubernetes,chestack/kubernetes,roberthbailey/kubernetes,verult/kubernetes,roberthbailey/kubernetes,Acidburn0zzz/kubernetes,Clarifai/kubernetes,nckturner/kubernetes,krmayankk/kubernetes,krmayankk/kubernetes,jingxu97/kubernetes,fabriziopandini/kubernetes,linux-on-ibm-z/kubernetes,jessfraz/kubernetes,carlory/kubernetes,linux-on-ibm-z/kubernetes,sdminonne/kubernetes,micahhausler/kubernetes,andrewrynhard/kubernetes,jackfrancis/kubernetes,andrewrynhard/kubernetes,rrati/kubernetes,k82/kubernetes,nikhita/kubernetes,fanzhangio/kubernetes,ii/kubernetes,linux-on-ibm-z/kubernetes,deads2k/kubernetes,nckturner/kubernetes,cblecker/kubernetes,BenTheElder/kubernetes,warmchang/kubernetes,tpepper/kubernetes,mkumatag/kubernetes,matthyx/kubernetes,tpepper/kubernetes,BenTheElder/kubernetes,openshift/kubernetes,li-ang/kubernetes,cblecker/kubernetes,liggitt/kubernetes,ii/kubernetes,mikedanese/kubernetes,ii/kubernetes,enj/kubernetes,jackfrancis/kubernetes,saad-ali/kubernetes,mikedanese/kubernetes,lojies/kubernetes,ii/kubernetes,verult/kubernetes,Acidburn0zzz/kubernetes,aledbf/kubernetes,tpepper/kubernetes,saad-ali/kubernetes,kubernetes/kubernetes,mosoft521/kubernetes,Clarifai/kubernetes,soltysh/kubernetes,cofyc/kubernetes,mikebrow/kubernetes,dims/kubernetes,fanzhangio/kubernetes,PI-Victor/kubernetes,zhouhaibing089/kubernetes,chestack/kubernetes,idvoretskyi/kubernetes,nikhita/kubernetes,mahak/kubernetes,jessfraz/kubernetes,wongma7/kubernetes,MikeSpreitzer/kubernetes,chestack/kubernetes,carlory/kubernetes,alejandroEsc/kubernetes,liggitt/kubernetes,zhangmingld/kubernetes,gnufied/kubernetes,fabriziopandini/kubernetes,hex108/kubernetes,idvoretskyi/kubernetes,mikedanese/kubernetes,andrewrynhard/kubernetes,rnaveiras/kubernetes,rrati/kubernetes,deads2k/kubernetes,mengqiy/kubernetes,roberthbailey/kubernetes,liggitt/kubernetes,alejandroEsc/kubernetes,olivierlemasle/kubernetes,warmchang/kubernetes,feiskyer/kubernetes,liggitt/kubernetes,dims/kubernetes,mosoft521/kubernetes,carlory/kubernetes,iameli/kubernetes,iameli/kubernetes,kevin-wangzefeng/kubernetes,mahak/kubernetes,jessfraz/kubernetes,kevin-wangzefeng/kubernetes,micahhausler/kubernetes,jagosan/kubernetes,Clarifai/kubernetes,PiotrProkop/kubernetes,k82/kubernetes,spzala/kubernetes,hex108/kubernetes,PI-Victor/kubernetes,rrati/kubernetes,zhouhaibing089/kubernetes,mkumatag/kubernetes,k82cn/kubernetes,alejandroEsc/kubernetes,rnaveiras/kubernetes,jagosan/kubernetes,ping035627/kubernetes,zhouhaibing089/kubernetes,warmchang/kubernetes,fanzhangio/kubernetes,rnaveiras/kubernetes,matthyx/kubernetes,wongma7/kubernetes,tengqm/kubernetes,jsafrane/kubernetes,kevin-wangzefeng/kubernetes,bparees/kubernetes,k82/kubernetes,linux-on-ibm-z/kubernetes,nckturner/kubernetes,humblec/kubernetes,jackfrancis/kubernetes,weiwei04/kubernetes,ping035627/kubernetes,monopole/kubernetes,fanzhangio/kubernetes,dims/kubernetes,csrwng/kubernetes,nak3/kubernetes,tengqm/kubernetes,gnufied/kubernetes,GulajavaMinistudio/kubernetes,idvoretskyi/kubernetes,nckturner/kubernetes,mosoft521/kubernetes,Clarifai/kubernetes,li-ang/kubernetes,sdminonne/kubernetes,PiotrProkop/kubernetes,mahak/kubernetes,lojies/kubernetes,GulajavaMinistudio/kubernetes,dereknex/kubernetes,bparees/kubernetes,ravilr/kubernetes,saad-ali/kubernetes,mengqiy/kubernetes,cblecker/kubernetes,jsafrane/kubernetes,wongma7/kubernetes,krmayankk/kubernetes,nikhita/kubernetes,openshift/kubernetes,kevin-wangzefeng/kubernetes,gnufied/kubernetes,roberthbailey/kubernetes,PI-Victor/kubernetes,feiskyer/kubernetes,x13n/kubernetes,iameli/kubernetes,cofyc/kubernetes,mosoft521/kubernetes,Clarifai/kubernetes,humblec/kubernetes,soltysh/kubernetes,matthyx/kubernetes,li-ang/kubernetes,mikebrow/kubernetes,Acidburn0zzz/kubernetes,Acidburn0zzz/kubernetes,BenTheElder/kubernetes,matthyx/kubernetes,k82cn/kubernetes,krmayankk/kubernetes,enj/kubernetes,humblec/kubernetes,ravilr/kubernetes,aledbf/kubernetes,PI-Victor/kubernetes,Acidburn0zzz/kubernetes,shyamjvs/kubernetes,MikeSpreitzer/kubernetes,enj/kubernetes,aledbf/kubernetes,thockin/kubernetes,rnaveiras/kubernetes,kubernetes/kubernetes,verb/kubernetes,jsafrane/kubernetes,saad-ali/kubernetes,dixudx/kubernetes,liggitt/kubernetes,mahak/kubernetes,zhangmingld/kubernetes,deads2k/kubernetes,zhangmingld/kubernetes,ping035627/kubernetes,aledbf/kubernetes,weiwei04/kubernetes,weiwei04/kubernetes,mikebrow/kubernetes,ii/kubernetes,dims/kubernetes,nckturner/kubernetes,mkumatag/kubernetes,enj/kubernetes,spzala/kubernetes,li-ang/kubernetes,jingxu97/kubernetes,hex108/kubernetes,fanzhangio/kubernetes,jsafrane/kubernetes,ping035627/kubernetes,nak3/kubernetes,thockin/kubernetes,andrewrynhard/kubernetes,iameli/kubernetes,matthyx/kubernetes,jingxu97/kubernetes,rafax/kubernetes,Acidburn0zzz/kubernetes,weiwei04/kubernetes,jsafrane/kubernetes,lojies/kubernetes,jagosan/kubernetes,cblecker/kubernetes,verult/kubernetes,lojies/kubernetes,nikhita/kubernetes,jagosan/kubernetes,mikebrow/kubernetes,tengqm/kubernetes,iameli/kubernetes,cblecker/kubernetes,olivierlemasle/kubernetes,GulajavaMinistudio/kubernetes,lojies/kubernetes,verb/kubernetes,gnufied/kubernetes,olivierlemasle/kubernetes,fanzhangio/kubernetes,dixudx/kubernetes,kubernetes/kubernetes,zhouhaibing089/kubernetes,nak3/kubernetes,k82cn/kubernetes,MikeSpreitzer/kubernetes,alejandroEsc/kubernetes,weiwei04/kubernetes,chestack/kubernetes,verb/kubernetes,fabriziopandini/kubernetes,soltysh/kubernetes,chrislovecnm/kubernetes,jingxu97/kubernetes,monopole/kubernetes,mosoft521/kubernetes,PiotrProkop/kubernetes,sdminonne/kubernetes,thockin/kubernetes,x13n/kubernetes,kubernetes/kubernetes,soltysh/kubernetes,tpepper/kubernetes,gnufied/kubernetes,olivierlemasle/kubernetes,bparees/kubernetes,chrislovecnm/kubernetes,rrati/kubernetes,olivierlemasle/kubernetes,monopole/kubernetes,jackfrancis/kubernetes,kubernetes/kubernetes,k82cn/kubernetes,ravilr/kubernetes,chestack/kubernetes,krmayankk/kubernetes,dixudx/kubernetes,jessfraz/kubernetes,tpepper/kubernetes,csrwng/kubernetes,hex108/kubernetes,krmayankk/kubernetes,verb/kubernetes,zhouhaibing089/kubernetes,GulajavaMinistudio/kubernetes,shyamjvs/kubernetes,enj/kubernetes,x13n/kubernetes,shyamjvs/kubernetes,mengqiy/kubernetes,roberthbailey/kubernetes,sdminonne/kubernetes,mahak/kubernetes,dims/kubernetes,dixudx/kubernetes,verb/kubernetes,dereknex/kubernetes,k82cn/kubernetes,dereknex/kubernetes,mengqiy/kubernetes,openshift/kubernetes,BenTheElder/kubernetes,bparees/kubernetes,x13n/kubernetes,nak3/kubernetes,dixudx/kubernetes,mikebrow/kubernetes,fabriziopandini/kubernetes,humblec/kubernetes,carlory/kubernetes,carlory/kubernetes,Clarifai/kubernetes,mkumatag/kubernetes,chrislovecnm/kubernetes,x13n/kubernetes,nak3/kubernetes,idvoretskyi/kubernetes,kevin-wangzefeng/kubernetes,wongma7/kubernetes,PiotrProkop/kubernetes,mengqiy/kubernetes,deads2k/kubernetes,chrislovecnm/kubernetes,andrewrynhard/kubernetes,mikedanese/kubernetes,warmchang/kubernetes,csrwng/kubernetes,sdminonne/kubernetes,thockin/kubernetes,hex108/kubernetes,shyamjvs/kubernetes,feiskyer/kubernetes,cofyc/kubernetes,humblec/kubernetes,ravilr/kubernetes,zhangmingld/kubernetes,csrwng/kubernetes,chrislovecnm/kubernetes,cofyc/kubernetes,nak3/kubernetes,csrwng/kubernetes,idvoretskyi/kubernetes,dereknex/kubernetes,aledbf/kubernetes,k82/kubernetes,PI-Victor/kubernetes,GulajavaMinistudio/kubernetes,monopole/kubernetes,dereknex/kubernetes,verult/kubernetes,tengqm/kubernetes,idvoretskyi/kubernetes,ravilr/kubernetes,saad-ali/kubernetes,rafax/kubernetes,soltysh/kubernetes,warmchang/kubernetes,PI-Victor/kubernetes,openshift/kubernetes,andrewrynhard/kubernetes,mikedanese/kubernetes,jessfraz/kubernetes,zhangmingld/kubernetes,rafax/kubernetes,fabriziopandini/kubernetes,shyamjvs/kubernetes,saad-ali/kubernetes,ping035627/kubernetes,monopole/kubernetes,thockin/kubernetes,spzala/kubernetes,chrislovecnm/kubernetes,dereknex/kubernetes,zhangmingld/kubernetes,li-ang/kubernetes,cofyc/kubernetes,feiskyer/kubernetes,verult/kubernetes,micahhausler/kubernetes,hex108/kubernetes,spzala/kubernetes,verult/kubernetes,rafax/kubernetes,rnaveiras/kubernetes,bparees/kubernetes,micahhausler/kubernetes,mkumatag/kubernetes