Follow up to r8839 with doc string fix:
Follow up to r8839 with doc string fix:

* subversion/libsvn_client/client.h
  (svn_client__get_auto_props): There is no provision for 'properties'
    being null, so don't imply that that's allowed.  Also, describe
    property hash keys and values, and allocation behavior, even
    though these things are probably obvious.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion