kmswebrtcendpoint: improve media_get_stream_id returning the id
kmswebrtcendpoint: improve media_get_stream_id returning the id

ISSUE:3672-trickle_ice
Change-Id: I2e542adc5f7cbe7b95199a3c4db81ad51a475e08

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