storage: Create error label path for storagePoolCreateXML
storage: Create error label path for storagePoolCreateXML

Rather than duplicate the error code, let's create an error
label to keep code common.

Signed-off-by: John Ferlan <87558058f6f829e5ec976c8ef960720af4ff9c7d@redhat.com>
ACKed-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>

jardasgit/libvirt,fabianfreyer/libvirt,eskultety/libvirt,crobinso/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,jardasgit/libvirt,zippy2/libvirt,fabianfreyer/libvirt,eskultety/libvirt,jardasgit/libvirt,crobinso/libvirt,andreabolognani/libvirt,eskultety/libvirt,fabianfreyer/libvirt,zippy2/libvirt,fabianfreyer/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,andreabolognani/libvirt,zippy2/libvirt,jfehlig/libvirt,nertpinx/libvirt,nertpinx/libvirt,nertpinx/libvirt,jardasgit/libvirt,olafhering/libvirt,jardasgit/libvirt,nertpinx/libvirt,jfehlig/libvirt,libvirt/libvirt,eskultety/libvirt,olafhering/libvirt,andreabolognani/libvirt,andreabolognani/libvirt,libvirt/libvirt,eskultety/libvirt,nertpinx/libvirt,crobinso/libvirt,olafhering/libvirt,jfehlig/libvirt,crobinso/libvirt,andreabolognani/libvirt,libvirt/libvirt