Work around .git in 'wildignore'

Closes #119.

plugin/fugitive.vim

@@ -818,13 +818,13 @@ function! s:Commit(args) abort
           let args = '--cleanup=strip '.args
         endif
         if bufname('%') == '' && line('$') == 1 && getline(1) == '' && !&mod
-          keepalt edit `=msgfile`
+          execute 'keepalt edit '.s:fnameescape(msgfile)
         elseif s:buffer().type() ==# 'index'
-          keepalt edit `=msgfile`
+          execute 'keepalt edit '.s:fnameescape(msgfile)
           execute (search('^#','n')+1).'wincmd+'
           setlocal nopreviewwindow
         else
-          keepalt split `=msgfile`
+          execute 'keepalt split '.s:fnameescape(msgfile)
         endif
         let b:fugitive_commit_arguments = args
         setlocal bufhidden=delete filetype=gitcommit