Fix #2915
Fix #2915

Add forward slash cleanup of the app name for the git-upload-pack
command. Prevents is_valid_app_name from removing the application folder
on `git fetch`.

progrium/dokku,jimjag/dokku,elia/dokku,progrium/dokku,progrium/dokku,alexquick/dokku,claytonbrown/dokku,jimjag/dokku,jimjag/dokku,dokku/dokku,progrium/dokku,claytonbrown/dokku,dokku/dokku,elia/dokku,dokku/dokku,alexquick/dokku,dokku/dokku,alexquick/dokku,dokku/dokku,claytonbrown/dokku,elia/dokku,dokku/dokku,elia/dokku,claytonbrown/dokku,progrium/dokku,jimjag/dokku,progrium/dokku,jimjag/dokku,progrium/dokku,claytonbrown/dokku,alexquick/dokku,elia/dokku,elia/dokku,dokku/dokku,alexquick/dokku,elia/dokku,dokku/dokku,alexquick/dokku,claytonbrown/dokku,alexquick/dokku,progrium/dokku,jimjag/dokku,claytonbrown/dokku,elia/dokku,alexquick/dokku,claytonbrown/dokku,jimjag/dokku,jimjag/dokku