backup/restore: improve error message about restoring tags

Before reporting a tag as not restored, verify if it really wasn't
restored. Generally created-by-* tags cannot be created manually. But
when restoring a backup in dom0, created-by-dom0 tag is added, which in
many cases will match what want to be restored.

Adjust tests to check this too.

qubesadmin/backup/restore.py

@@ -2035,6 +2035,7 @@ class BackupRestore(object):
                 try:
                     new_vm.tags.add(tag)
                 except Exception as err:  # pylint: disable=broad-except
+                    if tag not in new_vm.tags:
                         self.log.error('Error adding tag %s to %s: %s',
                             tag, vm.name, err)
 

qubesadmin/tests/backup/backupcompatibility.py

@@ -1440,6 +1440,12 @@ class TC_10_BackupCompatibility(qubesadmin.tests.backup.BackupTestCase):
                     str(value).encode())] = b'0\0'
 
             for tag in vm['tags']:
+                if tag.startswith('created-by-'):
+                    self.app.expected_calls[
+                        (name, 'admin.vm.tag.Set', tag, None)] = b''
+                    self.app.expected_calls[
+                        (name, 'admin.vm.tag.Get', tag, None)] = b'0\0001'
+                else:
                     self.app.expected_calls[
                         (name, 'admin.vm.tag.Set', tag, None)] = b'0\0'
 
@@ -1727,6 +1733,7 @@ class TC_10_BackupCompatibility(qubesadmin.tests.backup.BackupTestCase):
         # retrieve calls from other multiprocess.Process instances
         while not qubesd_calls_queue.empty():
             call_args = qubesd_calls_queue.get()
+            with contextlib.suppress(qubesadmin.exc.QubesException):
                 self.app.qubesd_call(*call_args)
         qubesd_calls_queue.close()
 
@@ -1797,6 +1804,7 @@ class TC_10_BackupCompatibility(qubesadmin.tests.backup.BackupTestCase):
         # retrieve calls from other multiprocess.Process instances
         while not qubesd_calls_queue.empty():
             call_args = qubesd_calls_queue.get()
+            with contextlib.suppress(qubesadmin.exc.QubesException):
                 self.app.qubesd_call(*call_args)
         qubesd_calls_queue.close()
 
@@ -1867,6 +1875,7 @@ class TC_10_BackupCompatibility(qubesadmin.tests.backup.BackupTestCase):
         # retrieve calls from other multiprocess.Process instances
         while not qubesd_calls_queue.empty():
             call_args = qubesd_calls_queue.get()
+            with contextlib.suppress(qubesadmin.exc.QubesException):
                 self.app.qubesd_call(*call_args)
         qubesd_calls_queue.close()
 
@@ -1968,6 +1977,7 @@ class TC_10_BackupCompatibility(qubesadmin.tests.backup.BackupTestCase):
         # retrieve calls from other multiprocess.Process instances
         while not qubesd_calls_queue.empty():
             call_args = qubesd_calls_queue.get()
+            with contextlib.suppress(qubesadmin.exc.QubesException):
                 self.app.qubesd_call(*call_args)
         qubesd_calls_queue.close()