On the fsfs-format7 branch: extend fs_verify for format7 repos to check
L2P and P2L indexes for mutual consistency.

* subversion/include/svn_error_codes.h
  (SVN_ERR_FS_ITEM_INDEX_INCONSISTENT): new error code

* subversion/libsvn_fs_fs/fs_fs.c
  (verify_rep_cache): factor out from svn_fs_fs__verify
  (compare_l2p_to_p2l_index,
   compare_p2l_to_l2p_index,
   verify_index_consistency): implement two-way index consistency check
  (svn_fs_fs__verify): update


git-svn-id: https://svn.apache.org/repos/asf/subversion/branches/fsfs-format7@1476663 13f79535-47bb-0310-9956-ffa450edef68