Start using error wrapping with fmt.Errorf (#8588)

Use fatih/errwrap to fix all the code to use
error wrapping with fmt.Errorf()

cmd/object-api-multipart_test.go

@@ -237,8 +237,9 @@ func testPutObjectPartDiskNotFound(obj ObjectLayer, instanceType string, disks [
 	if err == nil {
 		t.Fatalf("Test %s: expected to fail but passed instead", instanceType)
 	}
+
 	// as majority of xl.json are not available, we expect uploadID to be not available.
-	expectedErr1 := InsufficientReadQuorum{}
+	expectedErr1 := BucketNotFound{Bucket: testCase.bucketName}
 	if err.Error() != expectedErr1.Error() {
 		t.Fatalf("Test %s: expected error %s, got %s instead.", instanceType, expectedErr1, err)
 	}
@@ -255,8 +256,8 @@ func testPutObjectPartDiskNotFound(obj ObjectLayer, instanceType string, disks [
 	}
 
 	// As all disks at not available, bucket not found.
-	expectedErr2 := errDiskNotFound
-	if err != errDiskNotFound {
+	expectedErr2 := BucketNotFound{Bucket: testCase.bucketName}
+	if err.Error() != expectedErr2.Error() {
 		t.Fatalf("Test %s: expected error %s, got %s instead.", instanceType, expectedErr2, err)
 	}
 }