Add debian support, fix syntax bug from RHEL version by zerlgi

Zerlgi:  

I note that your version differs significantly from the upstream version, not only by adding RHEL support but also in how it handles the ubuntu case from how the upstream version does so.  I assume this relates to the two years which have elapsed since the original garthk-mosh version was push'd to github.  

I also note that your version failed to add a test case with vagrant to exercise the rhel code.  My pull request also fails to offer a test case to exercise this code in debian.  (I still have a bit to learn about how to do TDD with puppet.  That learning curve is on my list).  

At any rate I have run a successful test of this on a debian jessie server in my cluster.  I'm about to test it on an ubuntu 14.02 installation on my local client machine.  Perhaps before you can act on this PR, I will have also added support for wheezy and squeeze as well.  (I note that http://mosh.mit.edu/ promises support for mosh with "squeeze-backports and later").  My cluster is primarily debian with a couple of machines running centOS and ubuntu.  If I had the time to dive into this, perhaps I could sort out how to use and extend the included vagrant file to test this with.  But that is unlikely.  This is a necessary diversion from mission critical work blocked by intermittent connections from my new provider which I hope mosh will help me resolve.  At any rate I should be able to at least manually test this in my own cluster.  

-- Hugh