Download etcdadm and nodeadm binaries automatically

[sarun87]

There is a need to download and place etcdadm and nodeadm binaries at proper locations before invoking the cctl create machine command. It would be great for cctl or http://github.com/platform9/ssh-provider to automatically download/compile these binaries on the target machine.

[jayunit100]

For now, unless someone is actively working on this, I'm going to propose merging my PR #174 as an example of what needs to be done (until a better solution is available), because it was a tricky (for me at least) to figure out all the parts, and we probably want a quick, easy to use example for users in the outside world who dont know how all the intricacies of compiling etcdadm, nodadm, and so on for linux. Specifically all these trivial but annoying little bits are taken care of:

• downloading binaries
• Where to put them
• installing docker
• making sure the directories have the right permissions
• not expecting to have write access to /etc on your machine that your using to run the installer