remove no-op synchronisation in executeCallbacksLoop

There's a lot of ceremony there, but if you look hard enough, you'll see
that there really isn't much guaranteed by doing so.
Merge pull request #71 from plobsing/no-sync

remove no-op synchronisation in executeCallbacksLoop
Reducing log in primecache.
Merge branch 'master' of github.com:youtube/vitess
Adding a flag to delay rebuilding serving graph.

Useful for doing one cell at a time.
Do not use obsolete SrvKeyspace.Shards
Fixing display of served types.

It's easier to just use what we need, instead of some
random obscure way of getting the wrong data.
Fix keyspace_test
Fixing a log that's too verbose.
Merge branch 'liguo'
Healthcheck shouldn't start query service with filtered replication.

changeCallback is correct, but if healthcheck is enabled, it was
starting query service.

Also adding tests to double-check it works as expected for
vertical splits and resharding.
Merge branch 'master' of github.com:youtube/vitess
Merge branch 'master' into replication
Fix topology.py bug
Fix VTGate remote master code
Merge branch 'parser'
Only passing and logging extra env, not all of env, in tests.
Merge branch 'master' into replication
tabletmanager: add more keyrange restrictions on queries.

Change the tabletmanager to add query rules against update and delete to
check the keyspace_id if it's present. Previously, only inserts were
checked.
Add/Fix shard_conn error logging