Revert r1293375, to resolve a regression in an optimized code path of
svn_ra_replay_range() and other functions.

* subversion/libsvn_repos/replay.c
  (path_driver_cb_func): Reintroduce the dummy mode documented to apply
    to svn_ra_replay_range().

This will need a further tweak in the editor v2 code to fix the tests that
break by this change.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1482436 13f79535-47bb-0310-9956-ffa450edef68