Fixes and enhancements to 'svnadmin verify --check-ucs-normalization':
  - Fixed latent bug in pool usage in hash iteration callbacks;
  - Prevented duplicate warnings about mergeinfo path
    normalization and collisions;

This commit and log message violate the one-change-per-commit rule. Mea culpa.

* subversion/libsvn_repos/dump.c:
  (normalized_unique, normalized_collision): New; global static values for the
   normalization check hash tables.
  (check_path_normalization): Renamed from check_ucs_normalization.
  (struct extract_mergeinfo_paths_baton, extract_mergeinfo_paths,
   struct filter_mergeinfo_paths_baton, filter_mergeinfo_paths
   struct verify_mergeinfo_normalization_baton, verify_mergeinfo_normalization):
   New batons and hash iterators for more selective mergeinfo normalization.
  (struct check_mergeinfo_normalization_baton): Removed.
  (check_mergeinfo_normalization): New; replaces previous iterator.
   The actual mergeinfo normalization check driver.
  (dump_node): Replace mergeinfo normalization code by calling
   check_mergeinfo_normalization.
  (add_directory, add_file): Update use of check_path_normalization.
  (check_name_collision): Imbue implementation with knowledge about the
   difference between an iteration pool and a rather more permanent
   result pool. Also use normalized_unique and normalized_collision
   instead if local static equivalents.

* subversion/tests/cmdline/svnadmin_tests.py (verify_denormalized_names):
   Update test case, and specifically expect nothing on stderr.
* subversion/tests/cmdline/svnadmin_tests_data/normalization_check.dump:
   Added another revision for the updated verify_denormalized_names test.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1546363 13f79535-47bb-0310-9956-ffa450edef68