ListObjectsV1 requests unnecessarily fail with offline nodes (#10386)

ListObjectsV1 requests are actually redirected to a specific node, 
depending on the bucket name. The purpose of this behavior was
to optimize listing.

However, the current code sends a Bad Gateway error if the
target node is offline, which is a bad behavior because it means
that the list request will fail, although this is unnecessary since
we can still use the current node to list as well (the default behavior
without using proxying optimization)

Currently, you can see mint fails when there is one offline node, after
this PR, mint will always succeed.

cmd/handler-utils.go

@@ -19,6 +19,7 @@ package cmd
 import (
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -498,10 +499,9 @@ func proxyRequest(ctx context.Context, w http.ResponseWriter, r *http.Request, e
 		RoundTripper: ep.Transport,
 		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
 			success = false
-			w.WriteHeader(http.StatusBadGateway)
-		},
-		Logger: func(err error) {
-			logger.LogIf(GlobalContext, err)
+			if err != nil && !errors.Is(err, context.Canceled) {
+				logger.LogIf(GlobalContext, err)
+			}
 		},
 	})