Use a separate thread pool for checks.

Refs #5050

components/checker/checkercomponent.cpp

@@ -140,7 +140,7 @@ void CheckerComponent::CheckThreadProc(void)
 		Log(LogDebug, "checker", "Executing service check for '" + service->GetName() + "'");
 
 		CheckerComponent::Ptr self = GetSelf();
-		Utility::QueueAsyncCallback(boost::bind(&CheckerComponent::ExecuteCheckHelper, self, service));
+		m_Pool.Post(boost::bind(&CheckerComponent::ExecuteCheckHelper, self, service));
 
 		lock.lock();
 	}

components/checker/checkercomponent.h

@@ -92,6 +92,8 @@ private:
 	void NextCheckChangedHandler(const Service::Ptr& service);
 
 	void RescheduleCheckTimer(void);
+
+	ThreadPool m_Pool;
 };
 
 }