potential UCP service restart issue

[mapuri]

I need to try this out but here is brief of potential issue I see with our UCP start/stop script.

We use --fresh-install flag for service start which will cause fingerprint, instance-id and certs to be regenerated (with different values) and might break the UCP running on other nodes.

--fresh-install was added in #190 based on suggestions to overcome some UCP re-install issues and make install more reliable, but may be we will need a better fix here.