platedetector: Remove unused variable
platedetector: Remove unused variable

Change-Id: Ia235974e7163cbf1a3d6635ee94f6b45b6ce38aa

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