Fix test suite when mysqld is not installed
Fix test suite when mysqld is not installed

The fact being confined, no value was returned when mysqld was not
found.  Also stub the which method to fix the problem.

puppetlabs/puppetlabs-mysql,markasammut/puppetlabs-mysql,DavidS/puppetlabs-mysql,puppetlabs/puppetlabs-mysql,simp/puppetlabs-mysql,DavidS/puppetlabs-mysql,simp/puppetlabs-mysql,markasammut/puppetlabs-mysql