bugfix: fix exception Cannot parse "0000-00-00 00:00:00"

[lfyzjck]

…ps://github.com/tidb-incubator/TiBigData/issues/269

What is the purpose of the change

issue: https://github.com/tidb-incubator/TiBigData/issues/269 avoid exception Cannot parse "0000-00-00 00:00:00": Value 0 for monthOfYear must be in the range [1,12]

Brief change log

(for example:)

• The TaskInfo is stored in the blob store on job creation time as a persistent artifact
• Deployments RPC transmits only the blob storage reference
• TaskManagers retrieve the TaskInfo from the blob cache

Verifying this change

(Please pick either of the following options)

This change is a trivial rework / code cleanup without any test coverage.

(or)

This change is already covered by existing tests, such as (please describe tests).

(or)

This change added tests and can be verified as follows:

(example:)

• Added integration tests for end-to-end deployment with large payloads (100MB)
• Extended integration test for recovery after master (JobManager) failure
• Added test that validates that TaskInfo is transferred only once across recoveries
• Manually verified the change by running a 4 node cluster with 2 JobManagers and 4 TaskManagers, a stateful streaming program, and killing one JobManager and two TaskManagers during the execution, verifying that recovery happens correctly.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no)
• The public API: (no)
• The runtime per-record code paths (performance sensitive): (yes)

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)

[CLAassistant]

All committers have signed the CLA.

[humengyu2012]

/run-all-tests

[humengyu2012]

/run-all-tests

[humengyu2012]

/run-all-tests