autotest: fix race condition between cron crash_sender and test invoked

client/site_tests/logging_KernelCrash/logging_KernelCrash.py

 # Copyright (c) 2010 The Chromium OS 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 logging, os, re
 from autotest_lib.client.bin import site_crash_test, site_log_reader, \
      site_utils, test
 from autotest_lib.client.common_lib import error, utils
 
 
@@ skipping 51 matching lines @@
             raise error.TestFail('%s was not properly cleared' % _KCRASH_FILE)
 
 
     def _test_sender_send_kcrash(self):
         """Test that crash_sender properly sends the crash report."""
         if not self._consent:
             return
         kcrash_report = self._get_kcrash_name()
         if not os.path.exists(kcrash_report):
             raise error.TestFail('Crash report gone')
-        self._set_sending(True)
         result = self._call_sender_one_crash(
             report=os.path.basename(kcrash_report))
         if (not result['send_attempt'] or not result['send_success'] or
             result['report_exists']):
             raise error.TestFail('kcrash not sent properly')
         if result['exec_name'] != 'kernel' or result['report_kind'] != 'kcrash':
             raise error.TestFail('kcrash exec name or report kind wrong')
         if result['report_payload'] != kcrash_report:
             raise error.TestFail('Sent the wrong kcrash report')
 
 
     def run_once(self, is_before, consent):
         self._log_reader.set_start_by_reboot(-1)
         # We manage consent saving across tests.
         self._automatic_consent_saving = False
         self._consent = consent
         if is_before:
             self.run_crash_tests(['reporter_startup'], must_run_all=False)
             # Leave crash sending paused for the kernel crash.
             self._leave_crash_sending = False
         else:
             self.run_crash_tests(['reporter_startup',
                                   'reporter_kcrash_storage',
                                   'sender_send_kcrash'],
                                  clear_spool_first=False)