platedetector: Remove unused variable
platedetector: Remove unused variable

Change-Id: Ia235974e7163cbf1a3d6635ee94f6b45b6ce38aa

TribeMedia/kms-core,ESTOS/kms-core,TribeMedia/kms-core,TribeMedia/kms-core,shelsonjava/kms-core,Kurento/kms-core,Kurento/kms-core,ESTOS/kms-core,Kurento/kms-core,KurentoLegacy/gst-kurento-plugins,TribeMedia/kms-core,KurentoLegacy/gst-kurento-plugins,ESTOS/kms-core,KurentoLegacy/gst-kurento-plugins,shelsonjava/kms-core,shelsonjava/kms-core,shelsonjava/kms-core,KurentoLegacy/gst-kurento-plugins,ESTOS/kms-core,Kurento/kms-core