Point to the landscape 14.07 release PPA

There won't actually be anything in this PPA until the 18th, so we shouldn't merge it until then. (We should also test it once they release, just to make sure I haven't fatfingered the URL :)
Hi -- You'll need the url here.  ppa:landscape/14.07 will not work.  I think this is right:

    http://ppa.launchpad.net/landscape/14.07/ubuntu