client: fix loadCoordinators

Once we receive an error, we want to keep the first error and cancel the
context so all other requests quit.

The conditional was backwards, so we never canceled the other requests
and we never saved the first error, which also meant we never returned
an error.

pkg/kgo/client.go

@@ -819,7 +819,7 @@ func (cl *Client) loadCoordinators(reload bool, typ int8, names ...string) (map[
 
 	var mu sync.Mutex
 	m := make(map[string]*broker)
-	var errQuit error
+	var firstErr error
 
 	var wg sync.WaitGroup
 	for _, name := range names {
@@ -836,8 +836,8 @@ func (cl *Client) loadCoordinators(reload bool, typ int8, names ...string) (map[
 			defer mu.Unlock()
 
 			if err != nil {
-				if errQuit != nil {
-					errQuit = err
+				if firstErr == nil {
+					firstErr = err
 					cancel()
 				}
 				return
@@ -847,7 +847,7 @@ func (cl *Client) loadCoordinators(reload bool, typ int8, names ...string) (map[
 	}
 	wg.Wait()
 
-	return m, errQuit
+	return m, firstErr
 }
 
 func (cl *Client) handleAdminReq(ctx context.Context, req kmsg.Request) ResponseShard {