Fix JingleSession class to avoid bogus incompatible protocol error

Two issues fixed in the error message handling code:
 1. Error response to session-info message is interpreted as old peer
    that doesn't support current auth protocol. That's not necessary
    anymore.
 2. Errors received after session-terminate were not ignored as they
    should.

BUG=402735

Review URL: https://codereview.chromium.org/493573002

Cr-Commit-Position: refs/heads/master@{#291730}
1 file changed