[OpenSIPS-Devel] [OpenSIPS/opensips] dfaa65: Fix db backend init for trace_id's

[Bogdan Andrei IANCU]

  Branch: refs/heads/3.0
  Home:   https://github.com/OpenSIPS/opensips
  Commit: dfaa654ac0cd7c76839c6fb8c1d1dddd2b95de8b
      https://github.com/OpenSIPS/opensips/commit/dfaa654ac0cd7c76839c6fb8c1d1dddd2b95de8b
  Author: Bogdan-Andrei Iancu <bogdan at opensips.org>
  Date:   2020-01-27 (Mon, 27 Jan 2020)

  Changed paths:
    M modules/tracer/tracer.c

  Log Message:
  -----------
  Fix db backend init for trace_id's

Do not perform DB queries during cfg parsing, but only at mod_init stage, as some DB backends (like db_text) may not be initialized before mod_init.

Closes #1947

(cherry picked from commit b4fce7b66d8478c6b3dc5684f2533140b88dc078)