security: Don't skip label restore on file systems lacking XATTRs

security: Don't skip label restore on file systems lacking XATTRs

The way that virSecurityDACRecallLabel is currently written is
that if XATTRs are not supported for given path to the caller
this is not different than if the path is still in use. The value
of 1 is returned which makes secdrivers skip label restore.
This is clearly a bug as we are not restoring labels on say NFS
even though previously we were.

Strictly speaking, changes to virSecurityDACRememberLabel are not
needed, but they are done anyway so that getter and setter behave
in the same fashion.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Cole Robinson <crobinso@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>