fix: get vim's source from GitHub

Author: niklaas

Diff for: .travis.yml

@@ -3,7 +3,7 @@ language: vim
 
 before_script: |
   git clone https://github.com/junegunn/vader.vim.git
-  hg clone https://code.google.com/p/vim/
+  git clone https://github.com/vim/vim.git
   cd vim
   ./configure --with-features=huge
   make