Do not depend on fugitive for finding git root

Revert #239
Close #387

autoload/fzf/vim.vim

@@ -447,14 +447,7 @@ endfunction
 " GFiles[?]
 " ------------------------------------------------------------------
 
-" helper function to get the git root. Uses vim-fugitive if available for EXTRA SPEED!
 function! s:get_git_root()
-  if exists('*fugitive#repo')
-    try
-      return fugitive#repo().tree()
-    catch
-    endtry
-  endif
   let root = split(system('git rev-parse --show-toplevel'), '\n')[0]
   return v:shell_error ? '' : root
 endfunction