Next step in refactoring svnserve's server baton:
give client-specific data its separate data structure.
Update all struct users

* subversion/svnserve/server.h
  (client_info_t): factored out from ...
  (server_baton_t): ... this
  (get_client_info): declare new initialization helper

* subversion/svnserve/serve.c
  (log_server_error,
   log_command,
   log_authz_denied): update struct users
  (authz_check_access): update using local variable
  (current_access,
   send_mechs,
   create_fs_access,
   auth,
   lookup_access,
   must_have_access,
   do_change_rev_prop,
   commit,
   find_repos,
   fetch_base_func): update struct users
  (get_client_info): implement new initialization helper
  (serve): update, particularly the init code

* subversion/svnserve/cyrus_auth.c
  (try_auth,
   cyrus_auth_request): update struct users

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1529710 13f79535-47bb-0310-9956-ffa450edef68