add nl at the end of file

tests/sample_data/hg_pushlog.json

@@ -234,4 +234,4 @@
   ], 
   "user": "jdoe@mozilla.com"
  }
-}
+}

tests/sample_data/resultset_data.json

@@ -16,4 +16,4 @@
             "commit_timestamp": null
         }
     ]
-}
+}

tests/sample_data_generator.py

@@ -174,4 +174,4 @@ def result_set(**kwargs):
 
     defaults = json.loads(open(source_file).read())
     defaults.update(kwargs)
-    return defaults
+    return defaults

treeherder/etl/pushlog.py

@@ -64,4 +64,4 @@ class GitPushlogProcess(JsonExtractorMixin,
                         GitPushlogTransformerMixin,
                         ResultSetsLoaderMixin):
     def run(self, source_url, project):
-        pass
+        pass