server: always return None instead of sometimes returning "ok"

Previously some functions returned the string "ok".

nilmdb/server/nilmdb.py

@@ -417,7 +417,7 @@ class NilmDB(object):
         self._add_interval(stream_id, interval, row_start, row_end)
 
         # And that's all
-        return "ok"
+        return
 
     def _find_start(self, table, dbinterval):
         """

nilmdb/server/server.py

@@ -177,7 +177,6 @@ class Stream(NilmApp):
         dictionary"""
         data_dict = json.loads(data)
         self.db.stream_set_metadata(path, data_dict)
-        return "ok"
 
     # /stream/update_metadata?path=/newton/prep&data=<json>
     @cherrypy.expose
@@ -188,7 +187,6 @@ class Stream(NilmApp):
         should be a json-encoded dictionary"""
         data_dict = json.loads(data)
         self.db.stream_update_metadata(path, data_dict)
-        return "ok"
 
     # /stream/insert?path=/newton/prep
     @cherrypy.expose
@@ -247,7 +245,7 @@ class Stream(NilmApp):
             raise cherrypy.HTTPError("400 Bad Request", e.message)
 
         # Done
-        return "ok"
+        return
 
     # /stream/remove?path=/newton/prep
     # /stream/remove?path=/newton/prep&start=1234567890.0&end=1234567899.0

tests/test_client.py

@@ -220,7 +220,6 @@ class TestClient(object):
         data = timestamper.TimestamperRate(testfile, start, 120)
         result = client.stream_insert("/newton/prep", data,
                                       start, start + 119.999777)
-        eq_(result, "ok")
 
         # Verify the intervals.  Should be just one, even if the data
         # was inserted in chunks, due to nilmdb interval concatenation.