virsh-volume: Unify strigification of volume type
virsh-volume: Unify strigification of volume type

There were two separate places with that were stringifying type of a
volume. One of the places was out of sync with types implemented
upstream.

To avoid such problems in the future, this patch adds a common function
to convert the type to string and reuses it across the two said places.

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