On the 'move-tracking-2' branch: fix an editor shim callback problem.

The fetcher is only supposed to fetch regular props, but this one was
including 'entry props'. This was not causing a problem so far, but would do
so later if not fixed.

* subversion/include/private/svn_editor3.h
  (svn_editor3__shim_fetch_func_t): Document that only regular props should
    be included.

* subversion/libsvn_ra/ra_loader.c
  (fetch): Remove non-regular props.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/move-tracking-2@1625929 13f79535-47bb-0310-9956-ffa450edef68