update script should fail fast if permissions denied

[shalako]

Script should exit immediately after permission error; otw this can be missed as it scrolls by quickly and later you're left wondering why the release you deployed doesn't have the latest code.

$ ./update
++ dirname ./update
+ ./scripts/install-git-hooks
+ has_remote_branch
+ git rev-parse '@{u}'
+ git pull
Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.
+ git submodule foreach --recursive git submodule sync
Entering 'packages/ruby'
Entering 'shared'
Entering 'src/broker-registrar'
Entering 'src/cf-mysql-broker'
Entering 'src/github.com/cloudfoundry-incubator/cf-lager'
Entering 'src/github.com/cloudfoundry-incubator/cf-mysql-acceptance-tests'
Entering 'src/github.com/cloudfoundry-incubator/cf-test-helpers'
Entering 'src/github.com/cloudfoundry-incubator/galera-healthcheck'
Entering 'src/github.com/cloudfoundry-incubator/route-registrar'
Entering 'src/github.com/cloudfoundry-incubator/switchboard'
Entering 'src/github.com/cloudfoundry/mariadb_ctrl'
Entering 'src/github.com/erikstmartin/go-testdb'
Entering 'src/github.com/fraenkel/candiedyaml'
Entering 'src/github.com/go-sql-driver/mysql'
Entering 'src/github.com/nu7hatch/gouuid'
Entering 'src/github.com/onsi/ginkgo'
Entering 'src/github.com/onsi/gomega'
Entering 'src/github.com/pivotal-golang/lager'
Entering 'src/github.com/sclevine/agouti'
Entering 'src/github.com/tedsuo/ifrit'
Entering 'src/golang.org/x/crypto'
Entering 'src/gopkg.in/validator.v2'
+ git submodule update --init --recursive

[cf-gitbot]

We have created an issue in Pivotal Tracker to manage this. You can view the current status of your issue at: https://www.pivotaltracker.com/story/show/105491860.

[ljfranklin]

Thanks for typing this up @shalako. The story was accepted by @menicosia some time ago. Closing this out.