s3api: Put more information in the str() for InternalError
s3api: Put more information in the str() for InternalError

There are few things more frustrating when digging through a log than
finding a traceback that ends with

    raise InternalError('unexpected status code %d' % status)

while having no indication of what the status code was.

Change-Id: I08e9f7c0643ae0469bd1937a30c1c4477b67c31f

tipabu/swift,swiftstack/swift,tipabu/swift,openstack/swift,openstack/swift,openstack/swift,tipabu/swift,openstack/swift,swiftstack/swift,tipabu/swift,swiftstack/swift