Fix a pool usage problem I introduced in r1652987.
Fix a pool usage problem I introduced in r1652987.

* subversion/svndumpfilter/svndumpfilter.c
  (headers_dup): New.
  (new_revision_record): Duplicate the incoming headers before storing them.

git-svn-id: f8a4e5e023278da1e04e203c7fe051e3c4285d88@1653045 13f79535-47bb-0310-9956-ffa450edef68

YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion,YueLinHo/Subversion