Invoke script/rmmon automatically from script/deploy.

:warning: :rotating_light: Danger, danger. This will nuke *all* monitoring on the current account (from `~/.rackspace_cloud_credentials`), not just the developer.rackspace.com stuff. :rotating_light: :warning: 

That shouldn't be an issue for us because, as far as I know, those are the only monitoring checks on that account. Something to be aware of, though.

Of course the longer-term fix is to make the `rax_mon` modules more reliable.

Fixes #539.
> Come to think of it, could we execute this as a local script from within the monitoring Ansible role - as opposed to here in deploy - so the tag handling is left to Ansible?

Oh, that would be better.

Did you just want to shelve this and have me look into a real fix, though?