library/SIP_Templates: Fix wrong method name in tr_SIP_REGISTER

Change-Id: Ieec2124417a3294cfb469180f44285e880a46177
diff --git a/library/SIP_Templates.ttcn b/library/SIP_Templates.ttcn
index 7cb9d68..7de2d27 100644
--- a/library/SIP_Templates.ttcn
+++ b/library/SIP_Templates.ttcn
@@ -516,7 +516,7 @@
 	requestLine := tr_SIP_ReqLine(REGISTER_E, sip_url_host_port),
 	msgHeader := tr_SIP_msgh_std(call_id, from_addr, to_addr, contact,
 				     tr_Via_from(tr_HostPort(from_addr.addr.nameAddr.addrSpec.hostPort)),
-				     "INVITE", *, seq_nr,
+				     "REGISTER", *, seq_nr,
 				     expires := expires),
 	messageBody := body,
 	payload := omit