[Findit] Update try-job result in a transaction and fix bugs in unittests.

appengine/findit/waterfall/test/try_job_pipeline_test.py

 # Copyright 2015 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import json
 
 from common.git_repository import GitRepository
 from common.pipeline_wrapper import pipeline_handlers
 from common.waterfall import buildbucket_client
 from model import analysis_status
@@ skipping 105 matching lines @@
     self.execute_queued_tasks()
 
     try_job = WfTryJob.Get(master_name, builder_name, build_number)
     expected_suspected_cl = {
         'revision': 'rev2',
         'commit_position': '2',
         'url': 'url_2',
         'repo_name': 'chromium'
     }
 
+    analysis = WfAnalysis.Get(master_name, builder_name, build_number)
     expected_try_job_results = [
         {
             'report': {
                 'result': {
                     'rev1': 'passed',
                     'rev2': 'failed'
                 },
                 'metadata': {
                     'regression_range_size': 2
                 }
@@ skipping 32 matching lines @@
     build_number = 1
 
     root_pipeline = TryJobPipeline(
         master_name, builder_name, build_number, 'rev1', 'rev2', ['rev2'],
         TryJobType.COMPILE, [])
     root_pipeline._LogUnexpectedAbort(True)
 
     try_job = WfTryJob.Get(master_name, builder_name, build_number)
 
     self.assertIsNone(try_job)