Edits assert methods

Makes changes to the following files:
  tests/agentbase.py
  tests/alarm/partition/test_coordination.py
  tests/api/v2/test_alarm_scenarios.py
  tests/api/v2/test_event_scenarios.py
  tests/api/v2/test_list_resources_scenarios.py
  tests/api/v2/test_statistics_scenarios.py
  tests/compute/virt/vmware/test_inspector.py
  tests/ipmi/platform/test_ipmi_sensor.py
  tests/objectstore/test_swift.py
  tests/publisher/test_file.py
  tests/storage/test_storage_scenarios.py

Replaces assertTrue(a in b) with assertIn(a, b).

Change-Id: I00d6b194dab0026558376e2fb052ff7b094dff32
Merge "Edits assert methods"