Remove error package and cause functions (#5784)

cmd/bucket-policy-handlers.go

@@ -29,7 +29,6 @@ import (
 	mux "github.com/gorilla/mux"
 	"github.com/minio/minio-go/pkg/policy"
 	"github.com/minio/minio/cmd/logger"
-	"github.com/minio/minio/pkg/errors"
 	"github.com/minio/minio/pkg/wildcard"
 )
 
@@ -277,7 +276,6 @@ func (api objectAPIHandlers) PutBucketPolicyHandler(w http.ResponseWriter, r *ht
 	}
 
 	if err = objAPI.SetBucketPolicy(ctx, bucket, policyInfo); err != nil {
-		err = errors.Cause(err)
 		switch err.(type) {
 		case NotImplemented:
 			// Return error for invalid bucket name.