qemuSnapshotActiveInternalDeleteGetDevices: Add warning when deleting inconsistent snapshot
As explained in the commit which added the new internal snapshot
deletion code we don't want to do any form of strict checking whether
the libvirt metadata is consistent with the on-disk state as we didn't
historically do that.
In order to be able to spot the cases add a warning into the logs if
such state is encountered. While warnings are easy to miss it's the only
reasonable way to do that. Users will be encouraged to file an issue
with the information, without requiring them to enable debug logs as
the reproduction of that issue may include very old historical state.
The checker is deliberately added separately so that it can be easily
reverted once it's no longer needed.
Signed-off-by: Peter Krempa <pkrempa@redhat.com> Reviewed-by: Pavel Hrdina <phrdina@redhat.com>