Require Class['mysql::server'], not Service['mysqld'] when creating DB.

When using version >= 2.2 of the MySQL module, setting up the database
for Trove depended on the MySQL service (Service['mysqld']). However,
if the service is not managed by Puppet (e.g. it is managed through
Pacemaker instead), this would cause catalog compilation to fail because
there is no Service['mysqld']. This is the case when the MySQL module is
called with service_manage => false. Requiring Class['mysql::server']
instead fixes this.

Change-Id: I455d8e11d5ec18661fd18e797df9e5c7b654700d
Closes-Bug: 1349316
Merge "Require Class['mysql::server'], not Service['mysqld'] when creating DB."