Merge pull request #84 from alphagov/logstash_backdrop

Logstash backdrop
Add keychain and setup for jenkins user

We've been having issues with ssh agent forwarding and jenkins, which we
need to push data between our environments. Keychain is what GOV.UK uses
to manage the agent forwarding so we should use it too.
Move .bashrc config into deploy class

If we don't have a jenkins_key we don't really want to setup keychain so
move the inserting of .bashrc into the if in deploy.pp
Merge pull request #85 from alphagov/add-keychain-to-jenkins

Add keychain and setup for jenkins user
Add jenkins_publickey as something you can provide

In order for keychain to validate that it is working we need to provide
it a public key as well as private
Merge pull request #86 from alphagov/include-public-key

Add jenkins_publickey as something you can provide
Merge branch 'master' into logstash_backdrop