qemu: snapshot: Always save config XML after qemuDomainSnapshotCreateDiskActive
qemu: snapshot: Always save config XML after qemuDomainSnapshotCreateDiskActive

If there's an offline config definition save it unconditionally even if
it was not modified.

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

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