Improve logging

Add value_string describing UL and DL TBF states and use it for logging
errors while freeing TBFs.

Change-Id: I292ec81ab602c65ef86e6e3e85740182b63474b6
diff --git a/tests/tbf/TbfTest.err b/tests/tbf/TbfTest.err
index 2647551..c6bc1aa 100644
--- a/tests/tbf/TbfTest.err
+++ b/tests/tbf/TbfTest.err
@@ -563,7 +563,7 @@
 TBF(TFI=1 TLLI=0xf1000002 DIR=DL STATE=FLOW) the IMSI '001001000000002' was already assigned to another MS object: TLLI = 0xf1000001, that IMSI will be removed
 TBF(TFI=0 TLLI=0xf1000001 DIR=DL STATE=FLOW) changes state from FLOW to RELEASING
 TBF(TFI=0 TLLI=0xf1000001 DIR=DL STATE=RELEASING) free
-TBF(TFI=0 TLLI=0xf1000001 DIR=DL STATE=RELEASING) Software error: Pending downlink assignment. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
+TBF(TFI=0 TLLI=0xf1000001 DIR=DL STATE=RELEASING) Software error: Pending downlink assignment in state GPRS_RLCMAC_DL_ASS_SEND_ASS. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
 PDCH(TS 4, TRX 0): Detaching TBF(TFI=0 TLLI=0xf1000001 DIR=DL STATE=RELEASING), 1 TBFs, USFs = 00, TFIs = 00000002.
 Detaching TBF from MS object, TLLI = 0xf1000001, TBF = TBF(TFI=0 TLLI=0xf1000001 DIR=DL STATE=RELEASING)
 ********** TBF ends here **********
@@ -572,7 +572,7 @@
 Destroying MS object, TLLI = 0x00000000
 TBF(TFI=1 TLLI=0xf1000002 DIR=DL STATE=FLOW) changes state from FLOW to RELEASING
 TBF(TFI=1 TLLI=0xf1000002 DIR=DL STATE=RELEASING) free
-TBF(TFI=1 TLLI=0xf1000002 DIR=DL STATE=RELEASING) Software error: Pending downlink assignment. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
+TBF(TFI=1 TLLI=0xf1000002 DIR=DL STATE=RELEASING) Software error: Pending downlink assignment in state GPRS_RLCMAC_DL_ASS_SEND_ASS. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
 PDCH(TS 4, TRX 0): Detaching TBF(TFI=1 TLLI=0xf1000002 DIR=DL STATE=RELEASING), 0 TBFs, USFs = 00, TFIs = 00000000.
 Detaching TBF from MS object, TLLI = 0xf1000002, TBF = TBF(TFI=1 TLLI=0xf1000002 DIR=DL STATE=RELEASING)
 Destroying MS object, TLLI = 0xf1000002
@@ -1971,7 +1971,7 @@
 Old MS: TLLI = 0xf1223344, TA = 7, IMSI = 0011223344, LLC = 2
 UL RSSI of TLLI=0xf1223344: 31 dBm
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) free
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Software error: Pending downlink assignment. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Software error: Pending downlink assignment in state GPRS_RLCMAC_DL_ASS_SEND_ASS. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) stopping timer 3169.
 PDCH(TS 7, TRX 0): Detaching TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW), 0 TBFs, USFs = 00, TFIs = 00000000.
 Detaching TBF from MS object, TLLI = 0xf1223344, TBF = TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW)
@@ -2150,7 +2150,7 @@
 Old MS: TLLI = 0xf1223344, TA = 7, IMSI = 0011223344, LLC = 2
 UL RSSI of TLLI=0xf1223344: 31 dBm
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) free
-TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Software error: Pending downlink assignment. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
+TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) Software error: Pending downlink assignment in state GPRS_RLCMAC_DL_ASS_SEND_ASS. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
 TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW) stopping timer 3169.
 PDCH(TS 7, TRX 0): Detaching TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW), 0 TBFs, USFs = 00, TFIs = 00000000.
 Detaching TBF from MS object, TLLI = 0xf1223344, TBF = TBF(TFI=0 TLLI=0xf1223344 DIR=UL STATE=FLOW)
@@ -6636,7 +6636,7 @@
 DL packet loss of IMSI= / TLLI=0xffeeddcc: 78%
 TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=FLOW EGPRS) changes state from FLOW to RELEASING
 TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=RELEASING EGPRS) free
-TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=RELEASING EGPRS) Software error: Pending downlink assignment. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
+TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=RELEASING EGPRS) Software error: Pending downlink assignment in state GPRS_RLCMAC_DL_ASS_SEND_ASS. This may not happen, because the assignment message never gets transmitted. Please be sure not to free in this state. PLEASE FIX!
 PDCH(TS 4, TRX 0): Detaching TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=RELEASING EGPRS), 0 TBFs, USFs = 00, TFIs = 00000000.
 Detaching TBF from MS object, TLLI = 0xffeeddcc, TBF = TBF(TFI=0 TLLI=0xffeeddcc DIR=DL STATE=RELEASING EGPRS)
 Destroying MS object, TLLI = 0xffeeddcc