virsh-snapshot: Reject --no-metadata together with --print-xml
virsh-snapshot: Reject --no-metadata together with --print-xml

Manual for "virsh snapshot-create-as" states that --no-metadata and
--print-xml are incompatible. Honor this detail in the code.

jardasgit/libvirt,eskultety/libvirt,jfehlig/libvirt,agx/libvirt,shugaoye/libvirt,crobinso/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,siboulet/libvirt-openvz,shugaoye/libvirt,iam-TJ/libvirt,cbosdo/libvirt,andreabolognani/libvirt,zippy2/libvirt,elmarco/libvirt,elmarco/libvirt,zhlcindy/libvirt-1.1.4-maintain,iam-TJ/libvirt,siboulet/libvirt-openvz,jardasgit/libvirt,fabianfreyer/libvirt,datto/libvirt,eskultety/libvirt,taget/libvirt,trainstack/libvirt,eskultety/libvirt,jfehlig/libvirt,trainstack/libvirt,shugaoye/libvirt,libvirt/libvirt,VenkatDatta/libvirt,zhlcindy/libvirt-1.1.4-maintain,trainstack/libvirt,trainstack/libvirt,nertpinx/libvirt,trainstack/libvirt,olafhering/libvirt,siboulet/libvirt-openvz,elmarco/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,cbosdo/libvirt,olafhering/libvirt,zippy2/libvirt,jfehlig/libvirt,agx/libvirt,datto/libvirt,iam-TJ/libvirt,nertpinx/libvirt,datto/libvirt,rlaager/libvirt,rlaager/libvirt,olafhering/libvirt,taget/libvirt,taget/libvirt,zippy2/libvirt,rlaager/libvirt,cbosdo/libvirt,VenkatDatta/libvirt,andreabolognani/libvirt,trainstack/libvirt,VenkatDatta/libvirt,agx/libvirt,zhlcindy/libvirt-1.1.4-maintain,iam-TJ/libvirt,rlaager/libvirt,taget/libvirt,trainstack/libvirt,jardasgit/libvirt,siboulet/libvirt-openvz,andreabolognani/libvirt,agx/libvirt,libvirt/libvirt,crobinso/libvirt,iam-TJ/libvirt,shugaoye/libvirt,taget/libvirt,zippy2/libvirt,fabianfreyer/libvirt,cbosdo/libvirt,cbosdo/libvirt,eskultety/libvirt,VenkatDatta/libvirt,crobinso/libvirt,nertpinx/libvirt,elmarco/libvirt,iam-TJ/libvirt,shugaoye/libvirt,fabianfreyer/libvirt,andreabolognani/libvirt,crobinso/libvirt,zhlcindy/libvirt-1.1.4-maintain,elmarco/libvirt,andreabolognani/libvirt,nertpinx/libvirt,eskultety/libvirt,datto/libvirt,iam-TJ/libvirt,agx/libvirt,libvirt/libvirt,libvirt/libvirt,jfehlig/libvirt,VenkatDatta/libvirt,rlaager/libvirt,olafhering/libvirt,jardasgit/libvirt,zhlcindy/libvirt-1.1.4-maintain,datto/libvirt,siboulet/libvirt-openvz