make ZeroMQIPC.py work with eventlet 0.9.17 and beyond

The zmq.Poller implementation for eventlet no longer works with the totally
revamped zmq support strategy in eventlet 0.9.17 and beyond.

This code drops the zmq.Poller patch in favor of eventlet specific code in ZeroMQIPC.py.

Change-Id: I3f0a927359d23b1a61d1cb71c6abd042872536b3