Instead of using separate char arrays storing
parts of the SDP origin (in monologue), just
use the corresponding structure.
Deprecate unused parts used before.
Additionally add logic:
don't set `->session_sdp_orig` for monologues
with empty tags. This leads to setting origin line
to those monologues, which will later skip updating it
with its own (so real one).
This is fixes the case with the offer/answer model,
where offer always sets its origin for the other side,
meanwhile the other side hasn't given the answer yet.
Then later this answer related monologue never gets
its real origin.
For this sake also adopt logic of `sdp_version_check()`
which serves 'SDP-version' and 'force-increment-sdp-ver'
flags.
Change-Id: I17f3ff67e1b3dafca797c5feb876ebb238dceaa2
Donat Zenichev
9daa320c20