Create a branch to work on CONNECTORS-867.

git-svn-id: https://svn.apache.org/repos/asf/manifoldcf/branches/CONNECTORS-867@1560402 13f79535-47bb-0310-9956-ffa450edef68
Revamp of how locks are managed, which seems logically correct but doesn't yet pass tests.

git-svn-id: https://svn.apache.org/repos/asf/manifoldcf/branches/CONNECTORS-867@1560404 13f79535-47bb-0310-9956-ffa450edef68
Be more consistent about cleaning up on error.

git-svn-id: https://svn.apache.org/repos/asf/manifoldcf/branches/CONNECTORS-867@1560411 13f79535-47bb-0310-9956-ffa450edef68
Disable ordering constraint; tests now pass

git-svn-id: https://svn.apache.org/repos/asf/manifoldcf/branches/CONNECTORS-867@1560503 13f79535-47bb-0310-9956-ffa450edef68
Get it working, at least.  No hangs, but takes much longer than before

git-svn-id: https://svn.apache.org/repos/asf/manifoldcf/branches/CONNECTORS-867@1560515 13f79535-47bb-0310-9956-ffa450edef68
Fix the way we handle retirement of records from pool.

git-svn-id: https://svn.apache.org/repos/asf/manifoldcf/branches/CONNECTORS-867@1560527 13f79535-47bb-0310-9956-ffa450edef68
Partial fix for CONNECTORS-867.

git-svn-id: https://svn.apache.org/repos/asf/manifoldcf/trunk@1560561 13f79535-47bb-0310-9956-ffa450edef68