GODRIVER-1729 Fix test error for 1.15 (mongodb#496)

Author: Divjot Arora

bson/bsoncodec/default_value_decoders_test.go

@@ -1322,7 +1322,11 @@ func TestDefaultValueDecoders(t *testing.T) {
 					nil,
 					&bsonrwtest.ValueReaderWriter{BSONType: bsontype.String, Return: string("not-valid-%%%%://")},
 					bsonrwtest.ReadString,
-					errors.New("parse not-valid-%%%%://: first path segment in URL cannot contain colon"),
+					&url.Error{
+						Op:  "parse",
+						URL: "not-valid-%%%%://",
+						Err: errors.New("first path segment in URL cannot contain colon"),
+					},
 				},
 				{
 					"can set false",