Update to tox 1.6 and setup.py develop

Change-Id: Ie81f5ee5a8f7835f0600a4f4f46b25920d424e71
Fixed nova notifier unit test

This fixed the bug #1221033 caused by the latest nova chagnes.

Temproarily enlarge the max allowed connection to mongoDB as a
workaround for bug #1218488. That bug should be addressed by
https://review.openstack.org/44465

Change-Id: I49d82bcc2c1ac6481b0f5d321db2f70549a95d55
Disable the pymongo pooling feature for tests

Because pymongo doesn't close connection on .close() when we use its
pool, we disable the MongoClient pooling feature for running tests.

This allow to use a normal number of connection in mongod for test.

Fixes bug #1218488

Change-Id: Ie4c74620937816ed0592f5ac72de99dee3173ad8
Merge "Update to tox 1.6 and setup.py develop"