Reënable presence visibility permission checking now it's not used on redundant code paths

synapse/handlers/presence.py

@@ -150,10 +150,6 @@ class PresenceHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def is_presence_visible(self, observer_user, observed_user):
-        defer.returnValue(True)
-        # return
-        # FIXME (erikj): This code path absolutely kills the database.
-
         assert(observed_user.is_mine)
 
         if observer_user == observed_user:

tests/handlers/test_presence.py

@@ -196,8 +196,6 @@ class PresenceStateTestCase(unittest.TestCase):
             SynapseError
         )
 
-    test_get_disallowed_state.skip = "Presence permissions are disabled"
-
     @defer.inlineCallbacks
     def test_set_my_state(self):
         mocked_set = self.datastore.set_presence_state