imageoverlay: Fix synchronization with facedetector
imageoverlay: Fix synchronization with facedetector

Change-Id: Icd52792c23bd4e328a25fbb4230862a4b19cd402

Kurento/kms-elements,shelsonjava/kms-elements,shelsonjava/kms-elements,Kurento/kms-elements,TribeMedia/kms-elements,shelsonjava/kms-elements,Kurento/kms-elements,TribeMedia/kms-elements,TribeMedia/kms-elements