BTS: fix as_l1_count_paging(): use ispresent() instead of isvalue()

We actually need to check if a MI is present, i.e. not omit.

  ispresent(omit) => false
  isvalue(omit)   => true

Change-Id: I0e24e2aaa1f0da7ffdbc93ea4a19491e5dfb39b4
diff --git a/bts/BTS_Tests.ttcn b/bts/BTS_Tests.ttcn
index 9534a8b..a2b4af7 100644
--- a/bts/BTS_Tests.ttcn
+++ b/bts/BTS_Tests.ttcn
@@ -2869,7 +2869,7 @@
 		if (match(rr, tr_PAGING_REQ1)) {
 			num_paging_rcv_msgs := num_paging_rcv_msgs + 1;
 			num_paging_rcv_ids := num_paging_rcv_ids + 1;
-			if (isvalue(rr.msgs.rrm.pagingReq_Type1.mobileIdentity2)) {
+			if (ispresent(rr.msgs.rrm.pagingReq_Type1.mobileIdentity2)) {
 				num_paging_rcv_ids := num_paging_rcv_ids + 1;
 			}
 		} else if (match(rr, tr_PAGING_REQ2)) {
@@ -2880,7 +2880,7 @@
 			if (not tmsi_is_dummy(rr.msgs.rrm.pagingReq_Type2.mobileIdentity2)) {
 				num_paging_rcv_ids := num_paging_rcv_ids + 1;
 			}
-			if (isvalue(rr.msgs.rrm.pagingReq_Type2.mobileIdentity3)) {
+			if (ispresent(rr.msgs.rrm.pagingReq_Type2.mobileIdentity3)) {
 				num_paging_rcv_ids := num_paging_rcv_ids + 1;
 			}
 		} else if (match(rr, tr_PAGING_REQ3)) {