CLOUDSTACK-7566:Many jobs getting stuck in pending state and cloud is unusable.

(cherry picked from commit a2d85c8cae5f603bbcfcd3659c1207f0bfe461a7)

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>

Conflicts:
	framework/jobs/src/org/apache/cloudstack/framework/jobs/impl/AsyncJobManagerImpl.java