suites: Wait for BTS to connect to BSC before continuing

Change-Id: I027e3bfb8f470a811e65e718e2a8c46809fe6396
diff --git a/suites/smpp/esme_ms_sms_transaction.py b/suites/smpp/esme_ms_sms_transaction.py
index efc244c..adc9dae 100755
--- a/suites/smpp/esme_ms_sms_transaction.py
+++ b/suites/smpp/esme_ms_sms_transaction.py
@@ -20,6 +20,7 @@
 nitb.smsc.esme_add(esme)
 nitb.start()
 bts.start()
+wait(nitb.bts_is_connected, bts)
 
 esme.connect()
 nitb.subscriber_add(ms)