products_condense does not seem to work as desired

bad description, but I have a example data and test.

See the attached file, but we call 'util.products_condense' on the products data and it doesnt seem to move up some of the fields. I'd expect for most of the fields not marked sticky to bubble up.

Note, that sticky=None or sticky=[some, list] doesn't seem to be breaking it (ie, sticky=None still shows it).

Heres the test program:

#!/usr/bin/python

from simplestreams import util
import sys, copy

STICKY = ['ftype', 'md5', 'sha256', 'size', 'name', 'id']
STICKY = None

data = util.load_content(open(sys.argv[1], "r").read())
orig_data = copy.deepcopy(data)
util.products_condense(data, sticky=STICKY)
sys.stdout.write(util.dump_data(data))
sys.stdout.write("\n")

ProblemType: Bug
DistroRelease: Ubuntu 14.10
Package: python-simplestreams 0.1.0~bzr341-0ubuntu1
ProcVersionSignature: Ubuntu 3.15.0-5.10-generic 3.15.0-rc8
Uname: Linux 3.15.0-5-generic x86_64
ApportVersion: 2.14.3-0ubuntu1
Architecture: amd64
CurrentDesktop: Unity
Date: Mon Jun 9 09:09:33 2014
EcryptfsInUse: Yes
InstallationDate: Installed on 2011-10-19 (963 days ago)
InstallationMedia: Ubuntu 11.10 "Oneiric Ocelot" - Release amd64 (20111012)
PackageArchitecture: all
SourcePackage: simplestreams
UpgradeStatus: Upgraded to utopic on 2013-05-20 (385 days ago)