CLEANUP: auth: make the code build again with DEBUG_AUTH

Reported by Cyril Bonté, minor issue caused by recent ACL rework.
diff --git a/src/auth.c b/src/auth.c
index f737fce..c9f7e04 100644
--- a/src/auth.c
+++ b/src/auth.c
@@ -137,7 +137,7 @@
 
 #ifdef DEBUG_AUTH
 	fprintf(stderr, "cfg: user=%s, pass=%s, group_mask=%u, flags=%X",
-		u->user, u->pass, u->group_mask, u->flags);
+		u->user, u->pass, u->u.group_mask, u->flags);
 #endif
 
 	/*
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 5222652..ec15fba 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -6685,7 +6685,7 @@
 			fprintf(stderr, "group %s, id %d, mask %08X, users:", curuserlist->groups[g], g , 1 << g);
 
 			for (curuser = curuserlist->users; curuser; curuser = curuser->next) {
-				if (curuser->group_mask & (1 << g))
+				if (curuser->u.group_mask & (1 << g))
 					fprintf(stderr, " %s", curuser->user);
 			}