check query cache verification on mysql >= 5.6.8

Add query cache type verification
MySQL >= 5.6.8 has query_cache_type OFF by default. It will disables the entire cache. 
http://dev.mysql.com/doc/refman/5.6/en/server-system-variables.html#sysvar_query_cache_type
Merge pull request #44 from zequeitor/patch-1

check query cache verification on mysql >= 5.6.8