tests: correct version check in clientreactor test

Experimentally, `(3, 6, 3)` is less than `sys.version_info` on an actual
Python 3.6.3 installation. Let's just check `< (3, 6, 4)` instead of
`<= (3, 6, 3)` so we stop seeing this bogus failure.

Differential Revision: https://phab.mercurial-scm.org/D5502

tests/test-wireproto-clientreactor.py

@@ -601,7 +601,7 b' class StreamSettingsTests(unittest.TestC'
         self.assertEqual(meta[b'data'], response2)
 
 if __name__ == '__main__':
-    if (3, 6, 0) <= sys.version_info <= (3, 6, 3):
+    if (3, 6, 0) <= sys.version_info < (3, 6, 4):
         # Python 3.6.0 through 3.6.3 inclusive shipped with
         # https://bugs.python.org/issue31825 and we can't run these
         # tests on those specific versions of Python. Sigh.