server: reduce verbosity of Async Job Manager log messages (#3616)

On a Cloudstack instance with log verbosity set to INFO, there are 2 messages generated every 10 seconds about cleaning up expired async jobs. This makes the log messages much noisier than they need to be.

This PR reduces that message to trace level, since there are actually useful messages at INFO level in that class.

Author: richardlawley

framework/jobs/src/main/java/org/apache/cloudstack/framework/jobs/impl/AsyncJobManagerImpl.java

@@ -835,7 +835,7 @@ protected void runInContext() {
 
             public void reallyRun() {
                 try {
-                    s_logger.info("Begin cleanup expired async-jobs");
+                    s_logger.trace("Begin cleanup expired async-jobs");
 
                     // forcefully cancel blocking queue items if they've been staying there for too long
                     List<SyncQueueItemVO> blockItems = _queueMgr.getBlockedQueueItems(JobCancelThresholdMinutes.value() * 60000, false);
@@ -885,7 +885,7 @@ public void reallyRun() {
                         }
                     }
 
-                    s_logger.info("End cleanup expired async-jobs");
+                    s_logger.trace("End cleanup expired async-jobs");
                 } catch (Throwable e) {
                     s_logger.error("Unexpected exception when trying to execute queue item, ", e);
                 }