Move some 'svn ls' functions handling externals from externals.c to list.c,
as they aren't generally reusable anyway.

* subversion/libsvn_client/client.h
  (svn_client__list_internal): Make static.
  (svn_client__list_externals): Make static.

* subversion/libsvn_client/externals.c
  (list_external_items,
   svn_client__list_externals): Move to list.c

* subversion/libsvn_client/list.c
  (includes): Add svn_wc_private.h.
  (list_externals,
   list_internal): Add prototype.

  (svn_client__list_internal): Rename to ...
  (list_internal): ... this and add documentation from .h. Update caller.
  (wrap_list_error): New function, based on externals helper.
  (list_external_items): New function. Copied from svn_client__list_externals.
    Update caller.

  (svn_client_list3): Update caller.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1448339 13f79535-47bb-0310-9956-ffa450edef68