pjproject: avoid to fail the negotiation when TURN needs a retry

This aims to fix the some negotiation failure when:
UserA (TURN ipv4) calls UserB (ipv4 only)

In fact, the first user will take some time to know the userB
addresses to allow on the TURN. So, during this time, the TURN will
give some EPIPE errors. EPIPE is code 32 defined by 120032 in pjsip
(PJ_STATUS_FROM_OS(EPIPE)).

So previous code was a mistake

Change-Id: If38c5d36dc38bfe89e3b2ccfbf1b64c934639adb