[GITEA] Add repo empty check for branch feed

- If you attempted to get a branch feed on a empty repository, it would
result in a panic as the code expects that the branch exists.
- `context.RepoRefByType` would normally already 404 if the branch
doesn't exist, however if a repository is empty, it would not do this
check.
- Fix bug where `/atom/branch/*` would return a RSS feed.

(cherry picked from commit d27bcd98a4)
(cherry picked from commit c58566403d)
(cherry picked from commit b8b3f6ab8b)

routers/web/feed/render.go

@@ -8,11 +8,12 @@ import (
 )
 
 // RenderBranchFeed render format for branch or file
-func RenderBranchFeed(ctx *context.Context) {
-	_, _, showFeedType := GetFeedType(ctx.Params(":reponame"), ctx.Req)
-	if ctx.Repo.TreePath == "" {
-		ShowBranchFeed(ctx, ctx.Repo.Repository, showFeedType)
-	} else {
-		ShowFileFeed(ctx, ctx.Repo.Repository, showFeedType)
+func RenderBranchFeed(feedType string) func(ctx *context.Context) {
+	return func(ctx *context.Context) {
+		if ctx.Repo.TreePath == "" {
+			ShowBranchFeed(ctx, ctx.Repo.Repository, feedType)
+		} else {
+			ShowFileFeed(ctx, ctx.Repo.Repository, feedType)
+		}
 	}
 }