Minor gem updates
reraise Cocaine error if git fetch is unsuccessful

Make 3 attempts total and then bail.
Merge pull request #6 from square/raise-error-after-retries

re-raise Cocaine error if git fetch is unsuccessful
cocaine 0.5.3
Update gems, notably resque to 1.25.1
Merge pull request #9 from square/update-gems

Update gems, notably resque to 1.25.1
extract synchronize_cache_repo method in git_repo.rb

Brings kochiku-worker closer to the git_repo.rb in kochiku.
Mimic the submodule redirect logic in kochiku repo
Merge pull request #10 from square/rob/smarter-submodules-kw

Selectively redirect submodules to the cached repo
Ensure that cached repo is from the right URL.
Merge pull request #11 from square/more-stash

Ensure that cached repo is from the right URL.
Merge branch 'master' of https://github.com/square/kochiku-worker