tbf_dl: correct tbf name in log message for moving a DL TBF

It makes no sense to call functions on null pointer object. Use
the name of the old tbf.

Change-Id: I93b8c07a0b2de40a11e94fd6c212897cbe3b50ef
Reviewed-on: https://gerrit.osmocom.org/212
Tested-by: Jenkins Builder
Reviewed-by: Holger Freyther <holger@freyther.de>
diff --git a/tests/tbf/TbfTest.err b/tests/tbf/TbfTest.err
index 9bea2fd..4e83ce2 100644
--- a/tests/tbf/TbfTest.err
+++ b/tests/tbf/TbfTest.err
@@ -1868,7 +1868,7 @@
 - No gaps in received block, last block: BSN=0 CV=15
 Old MS: TLLI = 0xf1223344, TA = 7, IMSI = 0011223344, LLC = 0
 There is a new MS object for the same MS: (0xf1223344, '0011223344') -> (0xf5667788, '')
-(no TBF) IMSI 0011223344: moving DL TBF to new MS object
+TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=FINISHED) IMSI 0011223344: moving DL TBF to new MS object
 Detaching TBF from MS object, TLLI = 0xf1223344, TBF = TBF(TFI=0 TLLI=0xf1223344 DIR=DL STATE=FINISHED)
 Attaching TBF to MS object, TLLI = 0xf5667788, TBF = TBF(TFI=0 TLLI=0xf5667788 DIR=DL STATE=FINISHED)
 Modifying MS object, TLLI = 0xf5667788, IMSI '' -> '0011223344'