Fix error returned by delete operation (#663)

[ML-5583](https://jira.iguazeng.com/browse/ML-5583)

clients/py/tests/test_integration.py

@@ -21,7 +21,9 @@
 import v3io_frames as v3f
 from datetime import datetime
 import pytz
+
 from conftest import has_go, test_backends, protocols, has_session
+from v3io_frames import DeleteError
 
 tsdb_span = 5  # hours
 integ_params = [(p, b) for p in protocols for b in test_backends]
@@ -220,6 +222,10 @@ def test_kv_read_empty_df(framesd, session, protocol):
 
     client.delete(backend, tableName)
 
+    # calling delete again should raise an error
+    with pytest.raises(DeleteError):
+        client.delete(backend, tableName)
+
 
 @pytest.mark.skipif(not has_session, reason='No session found')
 @pytest.mark.skipif(not has_go, reason='Go SDK not found')

clients/py/v3io_frames/http.py

@@ -173,7 +173,7 @@ def _delete(self, backend, table, filter, start, end, if_missing, metrics):
         # TODO: Make it DELETE ?
         resp = self._session.post(url, headers=headers, json=request)
         if not resp.ok:
-            raise CreateError(resp.text)
+            raise DeleteError(resp.text)
 
     @connection_error(ExecuteError)
     def _execute(self, backend, table, command, args, expression):