Allow Keystone configuration to be overriden

This is our first attempt to allow a user to override variables within
Puppet.  Currently we'll be leverage Bash and Facter. If a user wants
to change the Keystone database to foobar, they would set the following:

  $ export FACTOR_keystone_db_name=foobar

before running Grunt.

Change-Id: I526a4a9688ac2afd6e65903c684611872f0b8597
Signed-off-by: Paul Belanger <paul.belanger@polybeacon.com>
Merge "Allow Keystone configuration to be overriden"