Fix DriveApiRequestsTest.EmptyBatchUploadRequest in official builds.

Fix DriveApiRequestsTest.EmptyBatchUploadRequest in official builds.

Official builds don't include strings for CHECKs, so don't check for text.
Right now, the test is failing like so when doing an official build:

..\..\google_apis\drive\drive_api_requests_unittest.cc(2000): error: Death test: request->Commit()
    Result: died but not with expected error.
  Expected: Check failed
Actual msg:

BUG=467929
TBR=hirono@chromium.org

Committed: https://crrev.com/932a905ff8eb8462af417bd038081db2954e133d
Cr-Commit-Position: refs/heads/master@{#325246}

[Nico, 2015-04-15 15:05:32]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-04-15 15:05:54]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1052553004/1

[commit-bot: I haz the power, 2015-04-15 15:30:51]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-15 15:31:57]

Patchset 1 (id:??) landed as
https://crrev.com/932a905ff8eb8462af417bd038081db2954e133d
Cr-Commit-Position: refs/heads/master@{#325246}

[hirono, 2015-04-16 03:33:21]

On 2015/04/15 15:31:57, I haz the power (commit-bot) wrote:
> Patchset 1 (id:??) landed as
> https://crrev.com/932a905ff8eb8462af417bd038081db2954e133d
> Cr-Commit-Position: refs/heads/master@{#325246}

Thank you for fixing this!