Fixing bug in DbMemory.del_list(), where if you passed a filter to delete the whole table it would give index out of bounds. Updated unit test to cover that case.

Change-Id: I1282bd637567ca651ffcd201edfc8ff9fd0950d7
Signed-off-by: Eduardo Sousa <eduardosousa@av.it.pt>
diff --git a/osm_common/tests/test_dbmemory.py b/osm_common/tests/test_dbmemory.py
index 0b62485..f73c317 100644
--- a/osm_common/tests/test_dbmemory.py
+++ b/osm_common/tests/test_dbmemory.py
@@ -217,7 +217,7 @@
     assert excinfo.value.http_code == http.HTTPStatus.NOT_FOUND
 
 @pytest.mark.parametrize("table, filter, expected_data", [
-#    ("test", {}, []),
+    ("test", {}, []),
     ("test", {"_id": 1}, [{"_id": 2, "data": 2}, {"_id": 3, "data": 3}]), 
     ("test", {"_id": 2}, [{"_id": 1, "data": 1}, {"_id": 3, "data": 3}]), 
     ("test", {"_id": 1, "data": 1}, [{"_id": 2, "data": 2}, {"_id": 3, "data": 3}]),