glance: make ImageForUpload symmetric with ImageDownload

In this patch:
* remove all the image related attributes from ImageForUpload
* add an Image attribute to ImageForUpload
* rename ImageForUpload to ImageUpload

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
glance: image creation should use metadata headers

In the image creation API the metadata is passed as headers (same as the
upload API).

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
resteasy: InputStreamProvider for byte streams

In order to support image uploads and downloads the InputStreamProvider
has been added to the resteasy connector.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
resteasy: remove the ClientRequestFactory

In order to better support concurrent requests and unclosed or pending
byte streams, the ClientRequestFactory has been removed.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
glance: add support to upload queued images

In order to support the upload of queued images a new method has been
introduced.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>
glance: image download should use the GET method

In order to properly download an image the http method HEAD has been
replaced with GET.

Signed-off-by: Federico Simoncelli <fsimonce@redhat.com>