For key searches, we don't have to special-case for idlen == 0.

memcmp() is defined to return 0 when the length param is 0.

src/keys.c

@@ -318,13 +318,9 @@ key_find(struct key_tree *tree_h, uint8_t *id, uint8_t idlen)
 	AN(tree_h);
 	if (VRBT_EMPTY(tree_h))
 		return NULL;
-	if (idlen != 0) {
-		keycmp.id = id;
-		keycmp.idlen = idlen;
-		key = VRBT_FIND(key_tree, tree_h, &keycmp);
-	}
-	else
-		key = VRBT_MIN(key_tree, tree_h);
+	keycmp.id = id;
+	keycmp.idlen = idlen;
+	key = VRBT_FIND(key_tree, tree_h, &keycmp);
 	CHECK_OBJ_ORNULL(key, KEY_MAGIC);
 	return (key);
 }