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.
> Did you just want to shelve this and have me look into a real fix, though?

No, if its not too much effort (< 1 hour) to invoke this from the monitoring role as a local script, I'd  rather do that first for this reason: I don't want to have to remember whether to run `rmmon` or not each time I deploy, especially since deployments don't (shouldn't?) happen too frequently and I might forget the rules. I'd rather it be automatically run whenever the monitoring role is included.