virsh-snapshot: Don't leak @then in cmdSnapshotList()
virsh-snapshot: Don't leak @then in cmdSnapshotList()

The variable is used inside a loop in which it's allocated in
each iteration. Bring it inside the loop so that g_autoptr()
kicks in each iteration.

Fixes: 3caa28dc50df7ec215713075d669b20bef6473a2
Signed-off-by: Michal Privoznik <83d82aaba2eed257f4814b0c239c260c4caaadf0@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

nertpinx/libvirt,nertpinx/libvirt,jfehlig/libvirt,jfehlig/libvirt,zippy2/libvirt,nertpinx/libvirt,crobinso/libvirt,olafhering/libvirt,olafhering/libvirt,jfehlig/libvirt,crobinso/libvirt,nertpinx/libvirt,zippy2/libvirt,zippy2/libvirt,libvirt/libvirt,jfehlig/libvirt,crobinso/libvirt,libvirt/libvirt,libvirt/libvirt,olafhering/libvirt,libvirt/libvirt,olafhering/libvirt,crobinso/libvirt,zippy2/libvirt,nertpinx/libvirt