BTS_Tests: do not connect to PCUIF socket if not used

The PCUIF connection involves a lot of frequent messages, such as
the TIME.ind and since recently DATA.ind with len=0.  As a result,
the test suite logs are getting unreadable due to lots of coding
warnings and port queueing notifications.

This change is aimed to improve the situation a bit, by establishing
the PCUIF connection only for those test cases which actually use it.

Side effects:

  * TC_pcu_socket_verify_info_ind becomes reliable, because the
    PCUIF establishment is done after the RSL bootstrapping;

  * TC_pcu_socket_connect_multi starts to fail, because it used
    to pass due to timeout, since not all messages are handled
    in the 'alt' statement.

Change-Id: I09ccb65ce94a41ffdad4e93da650c3f32d422af4
Related: OS#5083
diff --git a/bts/BTS_Tests_SMSCB.ttcn b/bts/BTS_Tests_SMSCB.ttcn
index 102e2ac..dda78fd 100644
--- a/bts/BTS_Tests_SMSCB.ttcn
+++ b/bts/BTS_Tests_SMSCB.ttcn
@@ -1051,7 +1051,7 @@
 testcase TC_etws_pcu() runs on test_CT {
 	timer T := 10.0;
 
-	f_init();
+	f_init_with_pcuif();
 	f_init_l1ctl();
 	f_l1_tune(L1CTL, ccch_mode := CCCH_MODE_COMBINED_CBCH);