kmslogooverlay: Not show image if it is NULL
kmslogooverlay: Not show image if it is NULL

Change-Id: I0e021b2bf653fda51d0800eff30656a8fa232724

Kurento/kms-filters,Kurento/kms-filters,shelsonjava/kms-filters,shelsonjava/kms-filters,TribeMedia/kms-filters,shelsonjava/kms-filters,TribeMedia/kms-filters,TribeMedia/kms-filters,Kurento/kms-filters