SIP_Emulation: Rename component id

Remove the dash character, since it makes it impossible to reference the
component name under TESTPORT_PARAMETERS in .default/.cfg files.

While at it, actually, allow the test to provide a full id instead of
always appending the suffix to it. This provides more freedom on the
testsuite to provide a fitting component name.

Change-Id: Iecefe7d98a5842872f1efc55e013f672186ef1a8
diff --git a/library/SIP_Emulation.ttcn b/library/SIP_Emulation.ttcn
index 1b357b7..a5ebcfb 100644
--- a/library/SIP_Emulation.ttcn
+++ b/library/SIP_Emulation.ttcn
@@ -226,9 +226,7 @@
 	SipCreateCallback create_cb
 };
 
-function f_init_sip(inout SIP_Emulation_CT ct, charstring id) {
-	id := id & "-SIP";
-
+function f_init_sip(inout SIP_Emulation_CT ct, charstring id := "SIP_EMU") {
 	var SipOps ops := {
 		create_cb := refers(SIP_Emulation.ExpectedCreateCallback)
 	};