ctrl: Introduce CTRL command subscriber.by-*.aud2g <algo[,ki]>

This command provides getter and setter to set and retrieve the
authentication data for 2g subscribers.

Change-Id: Ibebac232fa173bce8a075cacf477214d5bdb590f
Related: SYS#5993
diff --git a/src/hlr_vty_subscr.c b/src/hlr_vty_subscr.c
index 3813393..a9f461d 100644
--- a/src/hlr_vty_subscr.c
+++ b/src/hlr_vty_subscr.c
@@ -476,8 +476,8 @@
 
 #define MILENAGE_KEY_LEN 16
 
-static bool auth_algo_parse(const char *alg_str, enum osmo_auth_algo *algo,
-			    int *minlen, int *maxlen)
+bool auth_algo_parse(const char *alg_str, enum osmo_auth_algo *algo,
+		     int *minlen, int *maxlen)
 {
 	if (!strcasecmp(alg_str, "none")) {
 		*algo = OSMO_AUTH_ALG_NONE;