The response dictionary in _delete_segment attach's any error
it encounters to the dict key 'exception', all other response
dict's use 'error' to store the exception.
Changed to make it consistent and added tests
Also added a third branch in st_delete as messages
created in _delete_container where being silently dropped.
Change-Id: Ifbc3b1fae78910fbc6acf4a86cfb0f60bb1aa336
actual_md5 was being used instead of _actual_md5 only when assigning
the md5 object. This resulted in all checks and updates of the md5
to be skipped.
When fixed it revealed another bug that the md5 of the read content
is always checked even if there is no _expected_etag.
Added tests
Change-Id: Iaf1e21324ce592049d02cd5be123604b99833e86