Expose revert_internal() from libsvn_wc/adm_ops.c to other libsvn_wc files.

* subversion/libsvn_wc/adm_ops.c
  (revert_internal): Drop 'static', and rename to ...
  (svn_wc__revert_internal): ... this.
  (revert_changelist, revert_partial, svn_wc_revert4): Update callers.

* subversion/libsvn_wc/wc.h
  (svn_wc__revert_internal): Declare.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1428773 13f79535-47bb-0310-9956-ffa450edef68