mkimage-yum.sh: handle spaces properly & allow mutiple packages & groups
mkimage-yum.sh: handle spaces properly & allow mutiple packages & groups

Signed-off-by: Ankit Jain <4b31f193e6f02e017474ce8428bfdf2b91f14ed0@yahoo.co.in>

mikebrow/docker,djs55/docker,paralin/docker,jvanz/docker,ibuildthecloud/docker,konstruktoid/docker-1,dims/docker,jimjag/docker,moby/moby,yosifkit/docker,vdemeester/docker,kolyshkin/moby,unclejack/docker,moul/docker,gnailuy/docker,pradipd/moby,ibuildthecloud/docker,kolyshkin/moby,mahak/docker,docker/docker,moul/docker,tmp6154/docker,jameszhan/docker,jvanz/docker,rremer/moby,AkihiroSuda/docker,SvenDowideit/docker,Ramzec/docker,flavio/docker,kojiromike/docker,trebonian/docker,konstruktoid/docker-1,jlhawn/docker,ibuildthecloud/docker,bearstech/moby,moby/moby,gnailuy/docker,Mokolea/docker,yosifkit/docker,thaJeztah/docker,mikebrow/docker,jimjag/docker,trebonian/docker,Ramzec/docker,vdemeester/docker,nawawi/docker,djs55/docker,djs55/docker,flavio/docker,jameszhan/docker,crosbymichael/docker,bearstech/moby,yongtang/docker,kolyshkin/moby,konstruktoid/docker-upstream,cpuguy83/docker,ibuildthecloud/docker,flavio/docker,AkihiroSuda/docker,pradipd/moby,jthelin/docker,moby/moby,jameszhan/docker,pradipd/moby,justincormack/docker,paralin/docker,nalind/docker,estesp/docker,thaJeztah/docker,moby/moby,cpuguy83/docker,gnailuy/docker,crosbymichael/docker,moul/docker,yosifkit/docker,thaJeztah/docker,konstruktoid/docker-upstream,yosifkit/docker,Mokolea/docker,unclejack/docker,bearstech/moby,jimjag/docker,nawawi/docker,nalind/docker,nalind/docker,kojiromike/docker,tmp6154/docker,moul/docker,ibuildthecloud/docker,tmp6154/docker,mahak/docker,estesp/docker,Ramzec/docker,jimjag/docker,justincormack/docker,cpuguy83/docker,Ramzec/docker,docker/docker,dims/docker,konstruktoid/docker-upstream,rremer/moby,yongtang/docker,jlhawn/docker,jthelin/docker,yongtang/docker,justincormack/docker,rremer/moby,dims/docker,SvenDowideit/docker,AkihiroSuda/docker,estesp/docker,unclejack/docker,nawawi/docker,SvenDowideit/docker,docker/docker,trebonian/docker,konstruktoid/docker-upstream,AkihiroSuda/docker,paralin/docker,bearstech/moby,Mokolea/docker,jvanz/docker,gnailuy/docker,mahak/docker,paralin/docker,nalind/docker,kojiromike/docker,mikebrow/docker,mahak/docker,Mokolea/docker,cpuguy83/docker,thaJeztah/docker,vdemeester/docker,nawawi/docker,jlhawn/docker,trebonian/docker,konstruktoid/docker-1,flavio/docker,crosbymichael/docker