Fixing topology tee.

We had missed:
- the tablet updates need to keep a version map
- need to protect member variables with mutex
- implementing the tablet action parts.
Merge branch 'master' into resharding
Fixing fake zkocc keyspace encoding.
Fixing a crash bug in there.
Tee's UpdateTablet is now more resilient.

If UpdateTablet works on primary, but fails with no tablet
on secondary, create the tablet on secondary.
We also now remember the version map after an update.
Simplified Barnacle protocol.

Because we have per-client sessions, there's no need to use
transaction ids for transactions.
Merge branch 'master' of github.com:youtube/vitess