Revert revision 6920.  Which was a reversion of 6764.  Which was the following:
Revert revision 6920.  Which was a reversion of 6764.  Which was the
following:

   Stabilize mod_dav_svn URLs so that unedited copied subtree items
   always claim the same "created rev" (for version resource URL purposes
   and such) as the revision in which their copy was created.  This is a
   major boost to the cache-ability of DAV version resource URLs.
   
   * subversion/mod_dav_svn/util.c [reverted]
     (get_last_history_rev): New.
     (dav_svn_get_safe_cr): Use get_last_history_rev() instead of
       svn_fs_node_created_rev().

Which ... ended up breaking world.

Cross your fingers.  With this code re-enabled, I have successfully
performed ten (10) simultaneous checkouts of Subversion's source code,
with room in our Berkeley DB locks usage for ten times (yes, that's a
hundred) that.

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