[errors] de-specialize Transient in favor of Tags.

common/errors/walk_test.go

Index: common/errors/walk_test.go
diff --git a/common/errors/walk_test.go b/common/errors/walk_test.go
index 3ab63283c354bff5fb5b90e85dc53b20ffab34c5..e21e3b88d8d181b65d18a1384bb26b6a302c499f 100644
--- a/common/errors/walk_test.go
+++ b/common/errors/walk_test.go
@@ -67,7 +67,6 @@ func TestAny(t *testing.T) {
 			testErr,
 			MultiError{errors.New("other error"), MultiError{testErr, nil}},
 			Annotate(testErr).Reason("error test").Err(),
-			WrapTransient(MultiError{WrapTransient(testErr), nil, errors.New("other error")}),
 		} {
 			Convey(fmt.Sprintf(`Registers true for %T %v`, err, err), func() {
 				So(Any(err, filter), ShouldBeTrue)
@@ -95,7 +94,6 @@ func TestContains(t *testing.T) {
 		for _, err := range []error{
 			sentinel,
 			MultiError{errors.New("other error"), MultiError{sentinel, nil}},
-			WrapTransient(MultiError{WrapTransient(sentinel), nil, errors.New("other error")}),
 		} {
 			Convey(fmt.Sprintf(`Registers true for %T %v`, err, err), func() {
 				So(Contains(err, sentinel), ShouldBeTrue)