BSSAP_Adapter: Split f_bssap_start() from f_bssap_init()

In non-handler mode, the SCCP emulation is currently started before
there's a user registered to SCCP_SP_PORT.  If the first BSSMAP
package arrives from the network, then the SCCP_Emulation will crash
as it cannot deliver the resulting SCCP user primitive to the user.

Let's split start from initialization, so user code can still register
something to SCCP_SP_PORT before starting SCCP_Emulation.

Change-Id: I55c94f18531bb7e5369500dc90f4b0ff3a420774
diff --git a/bsc/BSC_Tests.ttcn b/bsc/BSC_Tests.ttcn
index 936544b..906e214 100644
--- a/bsc/BSC_Tests.ttcn
+++ b/bsc/BSC_Tests.ttcn
@@ -312,6 +312,8 @@
 		connect(self:BSSAP, g_bssap.vc_SCCP:SCCP_SP_PORT);
 		f_legacy_bssap_reset();
 	}
+	f_bssap_start(g_bssap);
+
 	f_ipa_ctrl_start(mp_bsc_ip, mp_bsc_ctrl_port);
 
 	f_init_mgcp("VirtMSC");