kmshttpendpoint: Do not return an error when no sample is retrieved
kmshttpendpoint: Do not return an error when no sample is retrieved

Change-Id: I032cb08efd7fac8b44a00a4f6035df2e17f1ccd4

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