libvlr: fix auth_fsm_term(): use proper value-string for cause

Change-Id: Ia0868dce2da5cb78c30cf518870c3d91144499b9
diff --git a/src/libvlr/vlr_auth_fsm.c b/src/libvlr/vlr_auth_fsm.c
index 5207464..b5052b0 100644
--- a/src/libvlr/vlr_auth_fsm.c
+++ b/src/libvlr/vlr_auth_fsm.c
@@ -257,7 +257,7 @@
 	LOGPFSM(fi, "Authentication terminating with result %s%s%s\n",
 		auth_fsm_result_str[result],
 		cause ? ", cause " : "",
-		cause ? get_value_string(gsm48_gmm_cause_names, cause) : "");
+		cause ? gsm48_reject_value_name(cause) : "");
 
 	/* Do one final state transition (mostly for logging purpose)
 	 * and set the parent_term_event according to result */