Resync RTP session in case of timestamp jump
Resync RTP session in case of timestamp jump

This will prevent the timestamp jump to occur between each call for DTX
if something goes wrong. It's handy as oRTP does not manage well
timestamp jump if it is not resynced.

Fixes: OS#1803
Change-Id: Iae5da832218dbd1ede7a9451102074f2a5eb66df

osmocom/libosmo-abis,osmocom/libosmo-abis,osmocom/libosmo-abis