Merge pull request #555 in FS/freeswitch from ~DRAGOS_OANCEA/freeswitch-dragos:opus-repacketization-toggle-fec to master

* commit 'd145111e':
  FS-8344: mod_opus: toggle FEC on the last frame which is to be packed, so that FEC will be only present on the first SILK frame of the next Opus frame (Opus repacketization).