tbf: Add counters for aborted TBF in state FLOW

Increment CTR_TBF_DL_ABORTED/CTR_TBF_UL_ABORTED if a TBF gets freed
that is still in state GPRS_RLCMAC_FLOW.

Sponsored-by: On-Waves ehf
diff --git a/src/bts.cpp b/src/bts.cpp
index 0d3e32a..c0918dd 100644
--- a/src/bts.cpp
+++ b/src/bts.cpp
@@ -52,8 +52,10 @@
 static const struct rate_ctr_desc bts_ctr_description[] = {
 	{ "tbf.dl.alloc",		"TBF DL Allocated     "},
 	{ "tbf.dl.freed",		"TBF DL Freed         "},
+	{ "tbf.dl.aborted",		"TBF DL Aborted       "},
 	{ "tbf.ul.alloc",		"TBF UL Allocated     "},
 	{ "tbf.ul.freed",		"TBF UL Freed         "},
+	{ "tbf.ul.aborted",		"TBF UL Aborted       "},
 	{ "tbf.reused",			"TBF Reused           "},
 	{ "tbf.alloc.algo-a",		"TBF Alloc Algo A     "},
 	{ "tbf.alloc.algo-b",		"TBF Alloc Algo B     "},