GTPv2_Templates: Make tr_GTP2C_DeleteSessionReq() easier to use by default

There's currently no user of this template, but there will be one in a
follow-up patch in MME_Tests.

- Set generic templates as default parameters, so it can match
  everything.
- Reorder parameters to follow the message fields more closely.
- Change/fix some template types in parameters which were not correct.

Change-Id: I38b6c51b78772bc01e7be916ba382cb78934864c
diff --git a/library/GTPv2_Templates.ttcn b/library/GTPv2_Templates.ttcn
index c09bca8..65bc559 100644
--- a/library/GTPv2_Templates.ttcn
+++ b/library/GTPv2_Templates.ttcn
@@ -939,12 +939,11 @@
 		privateExtension := omit
 	}});
 template (present) PDU_GTPCv2
-tr_GTP2C_DeleteSessionReq(template (present) OCT4 d_teid,
+tr_GTP2C_DeleteSessionReq(template (present) OCT4 d_teid := ?,
 			  template (present) OCT3 seq := ?,
-			  template (omit) GTP2C_Cause cause,
-			  template (present) FullyQualifiedTEID sender_fteid,
-			  template FullyQualifiedTEID_List teid_list,
-			  template (present) uint4_t bearer_id) :=
+			  template GTP2C_Cause cause := *,
+			  template (present) uint4_t bearer_id := ?,
+			  template FullyQualifiedTEID sender_fteid := *) :=
 tr_PDU_GTP2C(d_teid, seq, {
 	deleteSessionRequest := {
 		cause := fr_GTP2C_Cause(cause),