msc_a,vlr: rename ciphering_required to is_ciphering_to_be_attempted

Clarify the name to avoid confusion in upcoming patches.

This function actually returns whether any ciphering mode besides A5/0
is enabled, and does not imply that ciphering is mandatory. A5/0 may
well be allowed when this function returns true.

Related: OS#4830
Change-Id: Ia55085e3b36feb275bcf92fc91a4be7d1c24a6b9
diff --git a/src/libmsc/gsm_04_08.c b/src/libmsc/gsm_04_08.c
index 9d3b5a2..53cafa4 100644
--- a/src/libmsc/gsm_04_08.c
+++ b/src/libmsc/gsm_04_08.c
@@ -417,7 +417,7 @@
 				net->vlr, msc_a, vlr_lu_type, tmsi, imsi,
 				&old_lai, &msc_a->via_cell.lai,
 				is_utran || net->authentication_required,
-				msc_a_require_ciphering(msc_a),
+				msc_a_is_ciphering_to_be_attempted(msc_a),
 				lu->key_seq,
 				osmo_gsm48_classmark1_is_r99(&lu->classmark1),
 				is_utran,
@@ -818,7 +818,7 @@
 			 req->cm_service_type,
 			 &mi, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 msc_a_require_ciphering(msc_a),
+			 msc_a_is_ciphering_to_be_attempted(msc_a),
 			 req->cipher_key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, cm2_len),
 			 is_utran);
@@ -944,7 +944,7 @@
 			 VLR_PR_ARQ_T_CM_RE_ESTABLISH_REQ, 0,
 			 &mi, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 msc_a_require_ciphering(msc_a),
+			 msc_a_is_ciphering_to_be_attempted(msc_a),
 			 req->cipher_key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, cm2_len),
 			 is_utran);
@@ -1306,7 +1306,7 @@
 			 net->vlr, msc_a,
 			 VLR_PR_ARQ_T_PAGING_RESP, 0, &mi, &msc_a->via_cell.lai,
 			 is_utran || net->authentication_required,
-			 msc_a_require_ciphering(msc_a),
+			 msc_a_is_ciphering_to_be_attempted(msc_a),
 			 pr->key_seq,
 			 osmo_gsm48_classmark2_is_r99(cm2, classmark2_len),
 			 is_utran);