internal/acl: connect getfacl stderr

This shows whatever failure is happening in the cure container.

Signed-off-by: Ophestra <cat@gensokyo.uk>

internal/acl/acl_test.go

@@ -25,8 +25,7 @@ var (
 
 func TestUpdate(t *testing.T) {
 	if os.Getenv("GO_TEST_SKIP_ACL") == "1" {
-		t.Log("acl test skipped")
-		t.SkipNow()
+		t.Skip("acl test skipped")
 	}
 
 	testFilePath := path.Join(t.TempDir(), testFileName)
@@ -143,6 +142,7 @@ func (c *getFAclInvocation) run(name string) error {
 	}
 
 	c.cmd = exec.Command("getfacl", "--omit-header", "--absolute-names", "--numeric", name)
+	c.cmd.Stderr = os.Stderr
 
 	scanErr := make(chan error, 1)
 	if p, err := c.cmd.StdoutPipe(); err != nil {
@@ -254,7 +254,7 @@ func getfacl(t *testing.T, name string) []*getFAclResp {
 		t.Fatalf("getfacl: error = %v", err)
 	}
 	if len(c.pe) != 0 {
-		t.Errorf("errors encountered parsing getfacl output\n%s", errors.Join(c.pe...).Error())
+		t.Errorf("errors encountered parsing getfacl output\n%s", errors.Join(c.pe...))
 	}
 	return c.val
 }