Fix #647, fix #909 - Always parse delete object non-strict

When an object is deleted, the submitted object's values are
ignored except for the primary key. Therefore, there's no
need to validate them in strict mode.
This also disables the rules validator for deletion objects, re #909

irrd/updates/parser.py

@@ -92,7 +92,7 @@ def __init__(
                 )
             except ValueError:
                 pass
-            if self.non_strict_mode:
+            if self.non_strict_mode or delete_reason:
                 self.rpsl_obj_new = rpsl_object_from_text(rpsl_text_submitted, strict_validation=False)
 
             if self.rpsl_obj_new.messages.errors():

irrd/updates/tests/test_handler.py

@@ -1071,7 +1071,6 @@ def test_parse_invalid_object_delete_syntax(self, prepare_mocks):
                             {"name": "person", "value": "Placeholder Person Object"},
                             {"name": "nic-hdl", "value": "PERSON-TEST"},
                             {"name": "changed", "value": "changed@example.com 20190701 # comment"},
-                            {"name": "source", "value": "TEST"},
                         ]
                     },
                 ],
@@ -1110,12 +1109,8 @@ def test_parse_invalid_object_delete_syntax(self, prepare_mocks):
         person: Placeholder Person Object
         nic-hdl: PERSON-TEST
         changed: changed@example.com 20190701 # comment
-        source: TEST
         
-        ERROR: Mandatory attribute "address" on object person is missing
-        ERROR: Mandatory attribute "phone" on object person is missing
-        ERROR: Mandatory attribute "e-mail" on object person is missing
-        ERROR: Mandatory attribute "mnt-by" on object person is missing
+        ERROR: Primary key attribute "source" on object person is missing
         ERROR: Can not delete object: no object found for this key in this database.
  
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~