Refactor repo.isBare to repo.isEmpty #5629 (#5714)

* Refactor repo.isBare to repo.isEmpty #5629

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Remove Sync call

routers/api/v1/repo/file.go

@@ -39,7 +39,7 @@ func GetRawFile(ctx *context.APIContext) {
 	// responses:
 	//   200:
 	//     description: success
-	if ctx.Repo.Repository.IsBare {
+	if ctx.Repo.Repository.IsEmpty {
 		ctx.Status(404)
 		return
 	}