Fix DeviceManagementRequestAuthTest.CannotUseOAuthTokenAsAuthData in official builds.

Removed string from ASSERT_DEATH, because official tests strip
the string passed to CHECK(false) and LOG(FATAL).

Bug: 913441
Change-Id: Ib68905b60d214064f341262789b31f763e8108b3
Reviewed-on: https://chromium-review.googlesource.com/c/1370307Reviewed-by: Lutz Justen <ljusten@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#615558}

components/policy/core/common/cloud/device_management_service_unittest.cc

@@ -1195,7 +1195,7 @@ TEST_F(DeviceManagementRequestAuthTest, CannotUseOAuthTokenAsAuthData) {
       service_->CreateJob(DeviceManagementRequestJob::TYPE_POLICY_FETCH,
                           shared_url_loader_factory_));
   ASSERT_DEATH(request_job->SetAuthData(DMAuth::FromOAuthToken(kOAuthToken)),
-               "This method does not accept OAuth2");
+               "");
 }
 
 }  // namespace policy