grizzly: swift multi-range support

[Tom Fifield]

If https://review.openstack.org/#/c/14180/ gets merged, it adds a new feature to swift: multi-range support.

This change adds multi range retrieval to OpenStack Swift. For non-
segmented data object, a client can use HTTP Range header to specify
multiple ranges to retrieve sections of the data object.

This implementation currently does not support segmented data object
multi range retrieval. When a client sends a multi range request
against a segmented data object, Swift will return HTTP status code
200. Support for segmented data multi range retrieval will be added
in near future.

This implementation is to bring Swift closer to CDMI multi range
data retrieval standard. Once support for segemented data multi
range is added, Swift will be compliant with CDMI standard in
this area.

[Tom Fifield (fifieldt)]

Patch was merged

[Anne Gentle (annegentle)]

The range header is documented in http://api.openstack.org/api-ref-objectstorage-v1.html#storage_object_services.

I believe this to be sufficient documentation.