qemu: escape literal IPv6 address in NBD migration
qemu: escape literal IPv6 address in NBD migration

A literal IPv6 must be escaped, otherwise migration fails with:
unable to execute QEMU command 'drive-mirror': address resolution failed
for f0::0d:5901: Servname not supported for ai_socktype
since QEMU treats everything after the first ':' as the port.

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