Fix entrypoint of OneConvergencePlugin plugin

In setup.cfg entrypoint of OneConvergencePlugin is set incorrectly.
Used '.' instead of ':'.

Closes-bug: #1372810

Change-Id: Ic1e154cfcf8b13f021b0635238e07a0459a25a9e
Merge "Fix entrypoint of OneConvergencePlugin plugin"
Merge branch 'master' of https://github.com/openstack/quantum