[OpenSIPS-Devel] [OpenSIPS/opensips] cb424c: uac: Fix possible crash in display name fixup

[Liviu Chircu]

  Branch: refs/heads/master
  Home:   https://github.com/OpenSIPS/opensips
  Commit: cb424c7d869bd8ee366d1831dc678b199b131a36
      https://github.com/OpenSIPS/opensips/commit/cb424c7d869bd8ee366d1831dc678b199b131a36
  Author: Liviu Chircu <liviu at opensips.org>
  Date:   2020-01-23 (Thu, 23 Jan 2020)

  Changed paths:
    M modules/uac/uac.c

  Log Message:
  -----------
  uac: Fix possible crash in display name fixup

Some variables, such as $dlg_val, return {NULL, 0} strings instead of
{"", 0} (e.g. $var), causing the dereference op to crash.

(cherry picked from commit 53296244b33d20abbf0fca79f6ea5d27bdadaaa9)