In case we ever change our minds about not allowing svn: properties in the
--with-revprop list, add property name spelling checks.

* subversion/svn/svn.c (sub_main): Add ifdef'd-out example of property
   name spelling check for use with the --with-revprop option.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1470782 13f79535-47bb-0310-9956-ffa450edef68