Improve MS logging

Use same formatting similar to what's now used in TBF, which is far more
easy to grep and follow. This way one can easily follow what happens to
a given IMSI, a give TFI, a given TLLI, etc.

Change-Id: If9b325764c8fd540d60b6419f32223fd7f5a5898
diff --git a/tests/ulc/PdchUlcTest.err b/tests/ulc/PdchUlcTest.err
index 67aa1db..4954070 100644
--- a/tests/ulc/PdchUlcTest.err
+++ b/tests/ulc/PdchUlcTest.err
@@ -7,7 +7,7 @@
 PDCH(bts=0,trx=0,ts=0) Timeout for registered SBA (FN=72, TA=0)
 PDCH(bts=0,trx=0,ts=0) PDCH state: disabled => enabled
 Creating MS object, TLLI = 0x12345678
-MS(TLLI=0x12345678, IMSI=, TA=220, 0/0,) Attaching DL TBF: TBF(DL:TFI-0-0--1:STATE-NEW:GPRS:TLLI-0x12345678)
+MS(TLLI-0x12345678:TA-220:MSCLS-0-0) Attaching DL TBF: TBF(DL:TFI-0-0--1:STATE-NEW:GPRS:TLLI-0x12345678)
 PDCH(bts=0,trx=0,ts=0) Expiring FN=2715613 but previous FN=2715608 is still reserved!
 PDCH(bts=0,trx=0,ts=0) Timeout for registered POLL (FN=2715608, reason=UL_ASS): TBF(DL:TFI-0-0--1:STATE-NEW:GPRS:TLLI-0x12345678)
 PDCH(bts=0,trx=0,ts=0) Timeout for registered POLL (FN=2715613, reason=UL_ASS): TBF(DL:TFI-0-0--1:STATE-NEW:GPRS:TLLI-0x12345678)