Fix glance::db::mysql::mysql_module data mapping

puppet_mysql_version is mapped to glance::db::mysql_module when it
should instead map to glance::db::mysql::mysql_module

Change-Id: Ifa6cc3dd42dd2281fc79896dd5a7e2efb394bfaf
Closes-Bug: #1308547
Merge remote-tracking branch 'origin/master' into icehouse