Move some not update/add specific functions to a separate file.

* subversion/libsvn_wc/update_editor.c
  (includes): Remove unused usings.
  (svn_wc_check_root,
   svn_wc__is_wcroot,
   svn_wc__get_wc_root,
   svn_wc_get_actual_target2): Remove these functions.

* subversion/libsvn_wc/wcroot_anchor.c
  (svn_wc_check_root,
   svn_wc__is_wcroot,
   svn_wc__get_wc_root,
   svn_wc_get_actual_target2): Remove everything but these functions.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1427801 13f79535-47bb-0310-9956-ffa450edef68