MXS-2271 Monitor modifications always go through Monitor::configure()

Previously, runtime monitor modifications could directly alter monitor fields,
which could leave the text-form parameters and reality out-of-sync. Also,
the configure-function was not called for the entire monitor-object, only the
module-implementation.

Now, all modifications go through the overridden configure-function, which calls the
base-class function. As most configuration changes are given in text-form, this
removes the need for specific setters. The only exceptions are the server add/remove
operations, which must modify the text-form serverlist.

server/modules/monitor/csmon/csmon.cc

@@ -119,6 +119,11 @@ void CsMonitor::update_server_status(MXS_MONITORED_SERVER* srv)
 
 bool CsMonitor::configure(const MXS_CONFIG_PARAMETER* pParams)
 {
+    if (MonitorWorkerSimple::configure(pParams))
+    {
+        return false;
+    }
+
     m_primary = pParams->get_server("primary");
     return true;
 }