Use a valid e-mail for admin user in keystone

The default installation uses test@test.com as the e-mail address
for the admin user created in keystone. This patch changes that
e-mail to root@localhost, which is consistent with the addresses
set for the rest of the users.

Fixes bz#1020199

Change-Id: I480f1bd4188d65b5c32de113a07cbdd5ab9beb9d