Trigger CI Builds in hermit-shell

[xich]

hermit-shell is often broken by HERMIT changes. It would be nice to run the travis CI build for it whenever there is a push to this repo, so someone is notified.

Looks like we can adapt the method here:

http://eng.rightscale.com/2015/04/27/dependent-builds-in-travis.html

(I say adapt, because we'll want to change to make use of travis encryption to not have auth info in plaintext. I've done this before, but it'll take some testing.)

Related to ku-fpg/hermit-shell#38