Fixing an action cleanup bug.

After a failed action, we were recording the failure, but not
cleaning up the original action. And a test. Also some cleanup:
- added a 'vtctl ReadTabletAction command
- using it in tests to not wait random amounts of time
  (the added test time is less than the time gained!)
- also fixing parameter passing in tabletmanager.py test.
WaitForAction is not ZK specific.
Merge branch 'master' into replication
Merge branch 'master' of github.com:youtube/vitess
Update VTGate V2
queryservice: query rules extention

Add new action type for query rules to support RETRY errors.
Change table blacklist rule for vertical split to return RETRY errors.
Adding a GetKeyspace command and test.
Merge branch 'vtocc'
Merge branch 'master' of github.com:youtube/vitess
parser: improved tests & error messages (WIP)
parser: tokenizer tests and a bug fix
parser: failure cases for tokenizer (WIP)
parser: add missing test file for tokenizer
parser: stream plan & parsed_query tests

Coverage is at 94%. All required code paths
are now fully covered in sqlparser.
Adding a check for replication position post snapshot.
Merge branch 'parser'
Merge branch 'master' of github.com:youtube/vitess
Fixing keyspace rebuild to operate on the right cells.

Used to get the list of cells by looking at the cells that
contain a serving tablet in shard 0. Now use the intersection
of the union of all shard.Cells and the passed-in cell list.
bsongen: support for GOIMPORTS env var
Adding vtdb_logger object to python code.

It can be used to report stats in any other way than logging
(logging is the default behavior of the class).