Fix bundle install ran from puppet.
Fix bundle install ran from puppet.

When puppet was run by vagrant on the VM, the vagrant user's TMP
variable was leaking through to the bundle run, causing it to fail (on
Ubuntu TMp defaults to /tmp/users/<uid>, which isn't world writable)

Explicitly setting the TMP variable for the bundle run avoids this.

alphagov/ci-puppet,alphagov/ci-puppet,alphagov/ci-puppet,alphagov/ci-puppet