[doc] Fixed install.sh script URL, see issue #9 at github repo

Change-Id: I99eefd6313791d3b63822e54079dc7bc6c6505c8
Merge branch 'labs' of ssh://github.com/rafaelnp/rnpvim into labs

* 'labs' of ssh://github.com/rafaelnp/rnpvim:
  [plugin] Set up temporary vimshell insinde .vim