MXS-1848 Add initMonitor() and finishMonitor() functions.

Not called and implementations are dummies.

server/modules/monitor/grmon/grmon.cc

@@ -118,6 +118,18 @@ stopMonitor(MXS_SPECIFIC_MONITOR *mon)
     delete handle;
 }
 
+static MXS_SPECIFIC_MONITOR* initMonitor(MXS_MONITOR *mon,
+                                         const MXS_CONFIG_PARAMETER *params)
+{
+    ss_dassert(!true);
+    return NULL;
+}
+
+static void finishMonitor(MXS_SPECIFIC_MONITOR* mon)
+{
+    ss_dassert(!true);
+}
+
 /**
  * Diagnostic interface
  *
@@ -321,6 +333,8 @@ extern "C"
     {
         static MXS_MONITOR_OBJECT MyObject =
         {
+            initMonitor,
+            finishMonitor,
             startMonitor,
             stopMonitor,
             diagnostics,