Use module parameters in monitors

All monitors now declare the parameters that they use. This allows the
core to check the validity of the parameters before they are passed to the
monitor. It also simplifies the processing of the parameters as they are
guaranteed to be valid.

server/modules/monitor/mysqlmon.h

@@ -53,8 +53,6 @@
 
 MXS_BEGIN_DECLS
 
-#define MYSQLMON_DEFAULT_FAILCOUNT 5
-
 /**
  * The handle for an instance of a MySQL Monitor module
  */