improve rsync fetching
improve rsync fetching

1. Add timeouts options to rsync.
2. Prevent transfering symlinks (-L option to rsync).
3. Protect location args to rsync with "--".
4. If rsync fails, try again a few times.

rhansen/rpstir,rhansen/rpstir,rhansen/rpstir,rhansen/rpstir,rhansen/rpstir