Fix a few bugs in incremental FSFS hotcopy when copying packs.
Fix a few bugs in incremental FSFS hotcopy when copying packs.

* subversion/libsvn_fs_fs/fs_fs.c
  (hotcopy_io_copy_dir_recursively): Do not error if the destination
   directory already exists. Pass the path to the parent directory of
   the source file to hotcopy_io_dir_file_copy(), not the path of the
   source file itself.
  (hotcopy_remove_rev_files): Don't re-compute the shard dir path during
   the first iteration of the loop. Store the shard dir path in the scratch
   pool instead of the iterpool because it is used during more than one
   iteration.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion