playerendpoint: Reduce from error to warn if some media is not supported
playerendpoint: Reduce from error to warn if some media is not supported

Change-Id: Ib02c5f2e0ec745edc90d0c58c68b2f0e40287b28

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