enable pylint 'assignment-from-no-return' check

Pylint reports one false positive 'assigning from a function
without a return' error. Disable the check locally there,
and enable it globaly.

common/pylintrc

@@ -101,7 +101,6 @@ disable=
   E1002,
   E1101,
   E1102,
-  E1111,
   E1120,
   E1121,
   E1123,

master/buildbot/test/unit/test_util_misc.py

@@ -54,7 +54,8 @@ def test_fn_exception(self):
         @util.deferredLocked(l)
         def do_fail():
             raise RuntimeError("oh noes")
-        d = do_fail()
+        # using decorators confuses pylint and gives a false positive below
+        d = do_fail()           # pylint: disable=assignment-from-no-return
         def check_unlocked(_):
             self.assertFalse(l.locked)
         d.addCallbacks(lambda _ : self.fail("didn't errback"),