BTS_Tests: accept optional TestSpecUnion in t_Pars

Change-Id: I75462c3d30544bb87b578f2627b304cce57393e5
Related: SYS#4895, OS#4941
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index eff1277..8874d85 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -769,8 +769,9 @@
 }
 
 friend template ConnHdlrPars t_Pars(template RslChannelNr chan_nr,
-					template RSL_IE_ChannelMode chan_mode,
-					float t_guard := 20.0) := {
+				    template RSL_IE_ChannelMode chan_mode,
+				    template (omit) TestSpecUnion spec := omit,
+				    float t_guard := 20.0) := {
 	chan_nr := valueof(chan_nr),
 	chan_mode := valueof(chan_mode),
 	t_guard := t_guard,
@@ -794,7 +795,7 @@
 		ms_actual_ta := mp_ms_actual_ta_exp,
 		facch_enabled := false
 	},
-	spec := omit,
+	spec := spec,
 	encr := omit,
 	bts0_band := omit,
 	tsc := mp_tsc_def,