Fix for BUG#18023: IM: instance can be started several times;

monitor interval must be > 2sec.


server-tools/instance-manager/guardian.cc:
  Start instance only if it is really crashed.

server-tools/instance-manager/guardian.cc

@@ -138,11 +138,14 @@ void Guardian_thread::process_instance(Instance *instance,
         break;
     case JUST_CRASHED:
       if (current_time - current_node->crash_moment <= 2)
+      {
+        if (instance->is_crashed())
         {
           instance->start();
           log_info("guardian: starting instance %s",
                    instance->options.instance_name);
         }
+      }
       else
         current_node->state= CRASHED;
       break;
@@ -151,6 +154,8 @@ void Guardian_thread::process_instance(Instance *instance,
           monitoring_interval)
       {
         if ((current_node->restart_counter < restart_retry))
+        {
+          if (instance->is_crashed())
           {
             instance->start();
             current_node->last_checked= current_time;
@@ -158,6 +163,7 @@ void Guardian_thread::process_instance(Instance *instance,
             log_info("guardian: restarting instance %s",
                      instance->options.instance_name);
           }
+        }
         else
           current_node->state= CRASHED_AND_ABANDONED;
       }