Fix compile error on 1.7.x caused by the 1.7.x-r1574868 backport.

* subversion/libsvn_repos/dump.c
  (dump_node): Use baton value as boolean as dump_node as r1227815 didn't
    change the baton on this branch to the 1.8.x+ style.


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/1.7.x-r1227815-conflict@1642663 13f79535-47bb-0310-9956-ffa450edef68