bsc: add TC_stats_conn_fail

Verify that stat bts.N.chan.rf_fail_sdcch works correctly.

Related: SYS#4878
Change-Id: I310ea1609168bc26790875767943e0545ed05177
diff --git a/bsc/README.txt b/bsc/README.txt
index aa785ad..e992dba 100644
--- a/bsc/README.txt
+++ b/bsc/README.txt
@@ -62,7 +62,7 @@
 
 x no response to CHAN ACT
 x CONN FAIL IND from BTS
-** verify counter increment of BTS_CTR_CHAN_RF_FAIL
+xx verify counter increment of BTS_CTR_CHAN_RF_FAIL
 * no (or late?) response to RF CHAN REL
 * no (or late?) response to RLL RELEASE REQ
 x RLL messages on not-activated channels