fix cell identifier generation in ttcn3 paging tests

The cell identifier used by the paging tests is 001-01, i.e. uses a
2-digit MNC. With the introduction of 3-digit MNC support in osmo-bsc,
the paging tests became incompatible with a osmo-bsc config with:

  network country code 1
  mobile network code 1

Explicitly declare a Cell_Identity with 2-digit MNC (includes an 'f').

Also, fix f_enc_mcc_mnc to properly encode 2-digit MNC values.

Related: OS#2847
Change-Id: Ide5228b403e43de8649b6eda18749ea2a9f592a9
diff --git a/library/BSSMAP_Templates.ttcn b/library/BSSMAP_Templates.ttcn
index 77ff7e4..5d2bff2 100644
--- a/library/BSSMAP_Templates.ttcn
+++ b/library/BSSMAP_Templates.ttcn
@@ -665,7 +665,11 @@
 }
 
 private function f_enc_mcc_mnc(GsmMcc mcc, GsmMnc mnc) return OCT3 {
-	return hex2oct(mcc[1] & mcc[0] & mnc[2] & mcc[2] & mnc[1] & mnc[0]);
+	if (mnc[0] == 'f'H) {
+		return hex2oct(mcc[1] & mcc[0] & mnc[0] & mcc[2] & mnc[2] & mnc[1]);
+	} else {
+		return hex2oct(mcc[1] & mcc[0] & mnc[2] & mcc[2] & mnc[1] & mnc[0]);
+	}
 }
 
 template BSSMAP_FIELD_CellIdentification_CGI ts_BSSMAP_CI_CGI(GsmMcc mcc, GsmMnc mnc, GsmLac lac, GsmCellId ci) := {