tree dd79a4c52b8db426e0994d34fbf00ed143f0ab24
parent edf6fe75b72c10190057c65bdff467e5585ea6d7
author Alexander Couzens <lynxis@fe80.eu> 1480371734 +0100
committer Alexander Couzens <lynxis@fe80.eu> 1480371789 +0100

timer: only call the callback if not NULL

Fix a crash in osmo-sgsn.

Change-Id: I04d58d9580708cc0f6d0f4aa17d3e9f2c6235c8e