Use a dictionary instead of many small variables

See #48 (comment)

Author: somini

plugin/gv.vim

@@ -251,8 +251,10 @@ function! s:list(fugitive_repo, log_opts)
   let git_log_cmd = FugitiveShellCommand(git_args, a:fugitive_repo)
 
   let repo_short_name = fnamemodify(a:fugitive_repo.tree(), ':t')
-  let b:gv_opts = a:log_opts
-  let b:gv_repo_short_name = repo_short_name
+  let b:gv = {
+        \ 'opts': a:log_opts,
+        \ 'repo_short_name': repo_short_name,
+        \ }
   let bufname = repo_short_name.' '.join(a:log_opts)
   silent exe (bufexists(bufname) ? 'buffer' : 'file') fnameescape(bufname)