Add Liberty support.

Add keystone v3 support.  Now you can choose which version of keystone
to run... all combinations tested exception Juno with v3.

Make node type and link speed configurable.

Make token and session timeouts much longer by default (so people don't
get logged out so quickly), but also configurable.

Keystone is now served by WSGI through Apache on Kilo and Liberty.

Memcached keystone token caching is disabled for now; it causes
intermittent problems; so using SQL for now.

Add localhost to /etc/hosts file.  This doesn't cause problems anymore,
if it ever did.

We now use the `openstack' CLI command for >= Kilo, instead of the
per-service client CLI tools.

Stick with ovs agent even in Liberty -- even though the default is now
linuxbridge, it seems.

In general, get rid of nearly all the rest of the cat <<EOF ... EOF
stuff and replace it with crudini --set/--del.  A touch slower, but much
cleaner.

Also in general, improve the Kilo support so that it more closely
matches the docs.

Quit trying to apt-get packages if they're installed, unless the
user selects the new DO_APT_UPGRADE option.  Always install was nice
in the beginning, but it is no longer the best use case, and it can
cause uncertainty when failures happen (i.e., if new versions of
packages get installed that the scripts can't handle).  So now there
are three apt options in the scripts and in the geni-lib script:

DO_APT_UPDATE -- updates the apt cache (often hard to do pkg
  install/upgrade if the cache is out of date); defaults to 1
DO_APT_INSTALL -- if this is set 0, we don't install *anything*
  other than critical deps (think python-m2crypto); defaults to 1
DO_APT_UPGRADE -- if this is set 1, we always run apt-get install
  to either install and/or upgrade OpenStack packages and deps.
  The big change is that this now defaults to 0 -- so packages are
  not upgraded from their current versions if they exist.

These are a collection of scripts that install and configuration
Openstack Juno on Ubuntu 14 and onwards, within an Emulab/Apt/Cloudlab
testbed experiment.

(The included dh2048.pem is a time-saving optimization enabling faster
experiment swapins; it's optional.)