security: Don't stop restoring labels too early

security: Don't stop restoring labels too early

The point of virSecurityManagerRestoreAllLabel() function is to
restore ALL labels and be tolerant to possible errors, i.e.
continue restoring seclabels and NOT return early.

Well, in two implementations of this internal API this type of
problem was found:

1) virSecurityDACRestoreAllLabel() returned early if
   virSecurityDACRestoreGraphicsLabel() failed, or when
   def->sec->sectype equals to an impossible value.

2) virSecuritySELinuxRestoreAllLabel() returned early if
   virSecuritySELinuxRestoreMemoryLabel() failed.

Fix all three places.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>