In the 'fsfsfixer' script, change the default configuration from 'not
sharded' to 'sharded 1000', to match virtually all real repositories.

* contrib/server-side/fsfsfixer/fixer/find_good_id.py
  Remove the sharding config from here, and import settings from
  'fixer_config.py' instead, to keep all of the user settings together.

* contrib/server-side/fsfsfixer/fixer/fixer_config.py
  Add a 'REVS_PER_SHARD' configuration setting here, set to 1000.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1477715 13f79535-47bb-0310-9956-ffa450edef68