tornado: kqueue support doesn't work on MacOS+homebrew.

Not worth investigating for our purposes.  Just disable it like we did
epoll.

Change-Id: I41319d5fb6dc1669dc70aecfb888a99fbcd1267e
diff --git a/tornado/ioloop.py b/tornado/ioloop.py
index 49b9c15..a289786 100644
--- a/tornado/ioloop.py
+++ b/tornado/ioloop.py
@@ -675,7 +675,7 @@
 if False and hasattr(select, "epoll"):
     # Python 2.6+ on Linux
     _poll = select.epoll
-elif hasattr(select, "kqueue"):
+elif False and hasattr(select, "kqueue"):
     # Python 2.6+ on BSD or Mac
     _poll = _KQueue
 else: