Fix for bug 83872: Bugzilla no longer requires the Mysql Perl module, but the DBD::mysql Perl module, and has been this way for a while.  Fixing the version checks in checksetup.pl to check the correct module.  Also eliminates a DBD::mysql-specific database function call that is depricated in the current version of DBD_mysql.
Patch by Dave Miller <justdave@syndicomm.com>
r= jake@acutex.net, tara@tequilarista.org