Assertion when making call to any destination with unresolved host name (thanks Curt Sampson for the report)

[nanang]

The original report can be found ​here.

When I make a call to a SIPS URI with a host part that resolves to an
IP address, albeit one with nobody listening for SIP connections on it,
the program fails in the appropriate manner. However, when I make a call
with a SIPS URI that does not resolve in DNS (i.e., there's no A or any
other type of record for it), the program instead dies due to an ABRT
(6) signal, which appears to be due to the following assertion failure:

 ../src/pj/os_core_unix.c:1201: pj_mutex_lock: Assertion `mutex' failed.

Easily reproduced by making a call to any unresolved destination or via unresolved proxy without specifying DNS server and without STUN/ICE (synchronous media channel init).

[nanang]

(In [3965]) Fix #1459: returned back the old/1.x way of controlling dialog lifetime in pjsua_call_make_call().