MNCC: Properly terminate speech version array

MNCC has this weird encoding that the speech version array must
be terminated with one element '-1' at the end.  Let's make sure
our default complies to this rule.

Change-Id: I2e06ed1b558c58a62a00ea8d3573bb31c0c3e750
Related: OS#2853
diff --git a/library/MNCC_Types.ttcn b/library/MNCC_Types.ttcn
index f1d9e37..1d7980a 100644
--- a/library/MNCC_Types.ttcn
+++ b/library/MNCC_Types.ttcn
@@ -169,7 +169,7 @@
 	coding		:= 0,	/* GSM standard */
 	radio		:= 3,	/* FR/HR, FR preferred */
 	speech_ctm	:= 0,	/* not supported */
-	speech_ver	:= { 0, 2, 4, 1, 5 },
+	speech_ver	:= { 0, 2, 4, 1, 5, -1 },
 	data		:= omit
 };