Build on ubuntu 14.04 if libuv-dev is installed

[naufraghi]

It should be possible to pass cmake some variables to force the use of the bundled lib (https://github.com/neovim/neovim/search?utf8=%E2%9C%93&q=libuv) but I found no way to make cargo propagate them, so the easy fix is to remove the libuv-dev package.

[oakes]

Thanks!