Unable to setup percona cluster

The python-mysqldb package brings in mysql-common, this creates
a /etc/mysql/my.cnf, and as a result causes our problem.  Opted
to purge the package vs installing after percona to avoid excessive
dep order in our site.yml.
Merge pull request #178 from blueboxgroup/blueboxgroup/allow-percona-to-start

Unable to setup percona cluster