tbf: Learn and propagate the TLLI changes due a new P-TMSI

During a routing area update a new P-TMSI was assigned. During
the PACKET CONTROL ACK on the DL we notice the change of TLLI
but didn't propagate this. This means that a Routing Area Update
Complete was only sent after a new RACH request.

Addresses:
<0007> gprs_rlcmac_meas.cpp:103 UL RSSI of TLLI=0x88661bc6: -67 dBm
<0002> bts.cpp:945 Got ACK, but UL TBF is gone TLLI=0xe512eba3
<0007> gprs_rlcmac_meas.cpp:158 DL packet loss of IMSI=274080000004765 / TLLI=0xe512eba3: 0%
<0002> tbf.cpp:668 TBF TFI=0 TLLI=0x88661bc6 T3169 timeout during transsmission
<0002> tbf.cpp:690 - Assignment was on PACCH
<0002> tbf.cpp:694 - No uplink data received yet
diff --git a/tests/Makefile.am b/tests/Makefile.am
index a752067..415fb4d 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -1,6 +1,6 @@
 AM_CPPFLAGS = $(STD_DEFINES_AND_INCLUDES) $(LIBOSMOCORE_CFLAGS) $(LIBOSMOGB_CFLAGS) $(LIBOSMOGSM_CFLAGS) -I$(top_srcdir)/src/
 
-check_PROGRAMS = rlcmac/RLCMACTest alloc/AllocTest
+check_PROGRAMS = rlcmac/RLCMACTest alloc/AllocTest tbf/TbfTest
 noinst_PROGRAMS = emu/pcu_emu
 
 rlcmac_RLCMACTest_SOURCES = rlcmac/RLCMACTest.cpp
@@ -17,6 +17,14 @@
 	$(LIBOSMOCORE_LIBS) \
 	$(COMMON_LA)
 
+tbf_TbfTest_SOURCES = tbf/TbfTest.cpp
+tbf_TbfTest_LDADD = \
+	$(LIBOSMOGB_LIBS) \
+	$(LIBOSMOGSM_LIBS) \
+	$(LIBOSMOCORE_LIBS) \
+	$(COMMON_LA) \
+	$(top_builddir)/src/libgprs.la
+
 emu_pcu_emu_SOURCES = emu/pcu_emu.cpp emu/test_replay_gprs_attach.cpp \
 	emu/openbsc_clone.c emu/openbsc_clone.h emu/gprs_tests.h \
 	emu/test_pdp_activation.cpp
@@ -49,7 +57,8 @@
 EXTRA_DIST = \
 	testsuite.at $(srcdir)/package.m4 $(TESTSUITE)	\
 	rlcmac/RLCMACTest.ok rlcmac/RLCMACTest.err \
-	alloc/AllocTest.ok alloc/AllocTest.err
+	alloc/AllocTest.ok alloc/AllocTest.err \
+	tbf/TbfTest.ok tbf/TbfTest.err
 
 DISTCLEANFILES = atconfig