BSC_Tests: Fix TC_assignment_fr_a5_4

Don't expect the ASSIGNMENT to fail in case of unsupported A5/4,
but expect a CIPHERING MODE REJECT.

Change-Id: I15024f61e67795b7e5ce72e1b641db6ca92ff76d
diff --git a/bsc/MSC_ConnectionHandler.ttcn b/bsc/MSC_ConnectionHandler.ttcn
index 51ac650..f683ef4 100644
--- a/bsc/MSC_ConnectionHandler.ttcn
+++ b/bsc/MSC_ConnectionHandler.ttcn
@@ -104,7 +104,8 @@
 	RSL.send(ts_RSL_DATA_IND(chan_nr, link_id, enc_PDU_ML3_MS_NW(valueof(l3))));
 }
 
-function f_cipher_mode(OCT1 alg, OCT8 key, template OCT16 kc128 := omit) runs on MSC_ConnHdlr {
+function f_cipher_mode(OCT1 alg, OCT8 key, template OCT16 kc128 := omit, boolean exp_fail := false)
+runs on MSC_ConnHdlr {
 	var PDU_BSSAP bssap;
 	var RSL_Message rsl;
 
@@ -125,10 +126,18 @@
 		}
 	[] BSSAP.receive(tr_BSSMAP_CipherModeCompl) -> value bssap {
 		// bssap.bssmap.cipherModeComplete.chosenEncryptionAlgorithm.algoritmhIdentifier
-		setverdict(pass);
+		if (exp_fail == true) {
+			setverdict(fail, "Unexpected Cipher Mode Complete");
+		} else {
+			setverdict(pass);
+		}
 		}
 	[] BSSAP.receive(tr_BSSMAP_CipherModeRej) -> value bssap {
-		setverdict(fail, "Ciphering Mode Reject");
+		if (exp_fail == false) {
+			setverdict(fail, "Ciphering Mode Reject");
+		} else {
+			setverdict(pass);
+		}
 		}
 	}
 }