SELECT permission not needed for SHOW STATUS
support connecting without binding to a particular db

without this patch:
[2014-01-24 16:06:26,030] [Thread-1] MySQLCollector couldnt connect to
database (1044, "Access denied for user 'diamond-coll'@'127.0.0.1' to
database 'helloimadb'")

with this patch:
profit !!
Merge pull request #517 from Dieterbe/mysql_collector

Mysql collector