Implemented S3 multi-part upload functionality

[OpenStack Infra]

https://review.openstack.org/49316
commit aafc2b0e070967ad443c50ead911d21727a57844
Author: Masashi Ozawa <email address hidden>
Date: Wed Oct 2 15:51:30 2013 +0900

    Implemented S3 multi-part upload functionality

    Adding large images to glance now uses the S3 MultiPart Upload REST API.
    Added a unit test to upload images of various sizes to trigger the usage
    of the S3 Multipart Upload API and ensure that it is being exercised.

    DocImpact: The following parameters are added in glance-api.conf
    +# Size, in MB, should S3 start chunking image files
    +# and do a multipart upload in S3. The default is 100MB.
    +#s3_store_large_object_size = 100
    +
    +# Multipart upload part size, in MB, should S3 use when uploading
    +# parts. The size must be greater than or equal to
    +# 5MB. The default is 10MB.
    +#s3_store_large_object_chunk_size = 10
    +
    +# The number of thread pools to perform a multipart upload
    +# in S3. The default is 10.
    +#s3_store_thread_pools = 10

    Implements: blueprint s3-multi-part-upload
    Change-Id: I36e28e7944e57cd7ac05e46afac461ec10245c68

[Tom Fifield (fifieldt)]

This should be picked up in the next run of the autotools