core: Enable to inject a job in Execution..

core: enable to inject a job in ExecutionHandler

Change-Id: I2e2fb56663ca730b3fb98ad53e653d3584857540
Signed-off-by: Eli Mesika <emesika@redhat.com>
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=872719