Registry db api marker implementation does not respect sort_key/sort_dir

[Brian Waldon]

Here are all the images in my registry:
curl 'http://localhost:9191/images?sort_key=name&sort_dir=asc'
{"images": [{"name": "aki-tty", "container_format": "aki", "disk_format": "aki", "checksum": "3ed2965d3f8d877a3ee3e061fd648e9a", "id": 2, "size": 4404752}, {"name": "ami-tty", "container_format": "ami", "disk_format": "ami", "checksum": "10047a119149e08fb206eea89832eee0", "id": 3, "size": 25165824}, {"name": "ari-tty", "container_format": "ari", "disk_format": "ari", "checksum": "2d222d406f3ed30e03ed44123c33cba6", "id": 1, "size": 5882349}]}

I begin pagination with limit=1 with no marker:
curl 'http://localhost:9191/images?sort_key=name&sort_dir=asc&limit=1'
{"images": [{"name": "aki-tty", "container_format": "aki", "disk_format": "aki", "checksum": "3ed2965d3f8d877a3ee3e061fd648e9a", "id": 2, "size": 4404752}]}

To move on to the next page, I should use marker=2. As indicated in the original query, image 3 should be returned. Image 1 is actually returned:
curl 'http://localhost:9191/images?sort_key=name&sort_dir=asc&limit=1&marker=2'
{"images": [{"name": "ari-tty", "container_format": "ari", "disk_format": "ari", "checksum": "2d222d406f3ed30e03ed44123c33cba6", "id": 1, "size": 5882349}]}