Re-attempt to delete temporary upload if the file is locked by another process (#12447)

Replace all calls to os.Remove/os.RemoveAll by retrying util.Remove/util.RemoveAll and remove circular dependencies from util.

Fix #12339

Signed-off-by: Andrew Thornton <art27@cantab.net>
Co-authored-by: silverwind <me@silverwind.io>

modules/util/util_test.go

@@ -8,8 +8,6 @@ import (
 	"strings"
 	"testing"
 
-	"code.gitea.io/gitea/modules/setting"
-
 	"github.com/stretchr/testify/assert"
 )
 
@@ -46,39 +44,6 @@ func TestURLJoin(t *testing.T) {
 	}
 }
 
-func TestIsExternalURL(t *testing.T) {
-	setting.AppURL = "https://try.gitea.io"
-	type test struct {
-		Expected bool
-		RawURL   string
-	}
-	newTest := func(expected bool, rawURL string) test {
-		return test{Expected: expected, RawURL: rawURL}
-	}
-	for _, test := range []test{
-		newTest(false,
-			"https://try.gitea.io"),
-		newTest(true,
-			"https://example.com/"),
-		newTest(true,
-			"//example.com"),
-		newTest(true,
-			"http://example.com"),
-		newTest(false,
-			"a/"),
-		newTest(false,
-			"https://try.gitea.io/test?param=false"),
-		newTest(false,
-			"test?param=false"),
-		newTest(false,
-			"//try.gitea.io/test?param=false"),
-		newTest(false,
-			"/hey/hey/hey#3244"),
-	} {
-		assert.Equal(t, test.Expected, IsExternalURL(test.RawURL))
-	}
-}
-
 func TestIsEmptyString(t *testing.T) {
 
 	cases := []struct {