The script generated only users with the same first name. In
addition, only one change was created per user. In order to be able to
test whether users can be found by their first name, different first
names are used now. For each of those users, 1 to 5 changes are
created to reflect a more natural user base, on which statistics
don't yield the same values for all users. As we don't want to
possibly specify valid gmail accounts, we use another suffix for the
email address.
Change-Id: Ieea72bb45a374eebaa2c51ec74789b337f256958
28deb034d0