Stop re-using a single notify struct while loading a repository from a
dumpfile. While nice in theory it is easy to forget clearing out variables
in the struct, which our bindings then try to read on the next invocation.

As temporary -but safe to backport- intermediate step introduce a scratch/
iter pool to hold the notification struct, while the code doesn't have
proper scratch pools yet.

This resolves a segfault in the JavaHL tests on OpenBSD
Found by: stsp

* subversion/libsvn_repos/load-fs-vtable.c
  (parse_baton): Remove notify struct. Add notify pool.
  (new_revision_record,
   maybe_add_with_history,
   new_node_record,
   set_node_property,
   close_node,
   close_revision): Allocate notify struct instead of reusing.
  (svn_repos_get_fs_build_parser4): Update initialization.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1616131 13f79535-47bb-0310-9956-ffa450edef68