Increasing max_allowed_packet not possible in modern versions of MySQL

Issue Summary

As of MySQL 5.0.x the variable max_allowed_packet cannot be set per session, and as of 5.0.84 and 5.1.31 the variable is read-only. Setting this at run time only works in 4.1.x and before. This module should detect which version of MySQL is being used and display a message to the user saying that this variable will need to be altered in the server's configuration file my.cnf.

http://dev.mysql.com/doc/refman/4.1/en/server-system-variables.html#sysv...
http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysv...
http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysv...

I've also noted this in the issue queue for this module's successor, Drupal tweaks: #545126: Increasing max_allowed_packet not possible in modern version of MySQL