Add ycm message silence patch

This adds a patch to vim for the Valloric/YouCompleteMe#642 the issue has been reported upstream to vim https://groups.google.com/forum/#!topic/vim_dev/WeBBjkXE8H8 but the patch is not merged into master, yet. since I think a lot of people use the YouCompleteMe extension it might be worth it to apply the patch to vim.