Publish individual files in IPA post job

Consuming the tarball directly in devstack required devstack understand
too many specifics about the layout of the interior of the tarball.
Uploading the files independently allows devstack to pull them down and
put them in glance directly.

Once everything has been migrated to pull the individual files down,
I'll push another merge request to stop publishing ipa-coreos.tar.gz.

As a note, this is part of the larger effort documented here[1] to get
IPA in the Ironic gate.

Once this is merged, https://review.openstack.org/#/c/117384/ will be
updated to utilize IMAGE_URLS and existing tooling to get IPA ramdisks
into glance.

1: http://lists.openstack.org/pipermail/openstack-dev/2014-August/
   042357.html

Change-Id: Ifa0b450d37d57b5eded3f8260f895cd9e97fd39e
Merge "Publish individual files in IPA post job"