MINOR: log: add dup_logsrv() helper function

ease code maintenance by introducing dup_logsrv() helper function to
properly duplicate an existing logsrv struct.

(cherry picked from commit 969e212c663dbbfae4b432413f8363072c0834a5)
 [ad: picked for two next following patches. Some context adjustment
  required]
Signed-off-by: Amaury Denoyelle <adenoyelle@haproxy.com>
4 files changed