[NO ISSUE][RT] Remove Invalid Clear Queued Jobs API

- user model changes: no
- storage format changes: no
- interface changes: yes
  - Remove clearJobQueue from IJobManager.

Details:
- The current clearJobQueue API in IJobManager
  does not follow the typical job lifecycle.
  i.e. job lifecycle listener are not notified
  that the jobs were canceled. Since the API
  is not used, this change removes it to avoid
  any future invalid usage.

Change-Id: I1bff81fe9378f9bbc9dfb04a6a9826ee052f0965
Reviewed-on: https://asterix-gerrit.ics.uci.edu/2237
Sonar-Qube: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Contrib: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Integration-Tests: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
Reviewed-by: Till Westmann <tillw@apache.org>
diff --git a/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/IJobManager.java b/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/IJobManager.java
index cda3037..a9ddee3 100644
--- a/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/IJobManager.java
+++ b/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/IJobManager.java
@@ -125,9 +125,4 @@
      * @return the maximum number of jobs to queue before rejecting new jobs
      */
     int getJobQueueCapacity();
-
-    /**
-     * Clears all queued jobs
-     */
-    void clearJobQueue();
 }
diff --git a/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/JobManager.java b/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/JobManager.java
index ffb72c9..b728e73 100644
--- a/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/JobManager.java
+++ b/hyracks-fullstack/hyracks/hyracks-control/hyracks-control-cc/src/main/java/org/apache/hyracks/control/cc/job/JobManager.java
@@ -290,11 +290,6 @@
         return ccs.getCCConfig().getJobQueueCapacity();
     }
 
-    @Override
-    public void clearJobQueue() {
-        jobQueue.clear();
-    }
-
     private void pickJobsToRun() throws HyracksException {
         List<JobRun> selectedRuns = jobQueue.pull();
         for (JobRun run : selectedRuns) {