Ensure buildbot user has uid 1000

Change-Id: Ie1d1983b4afc4304735ac1668b0d4a4046145d06
Reviewed-on: http://review.couchbase.org/40562
Reviewed-by: Chris Hillery <ceej@couchbase.com>
Tested-by: Chris Hillery <ceej@couchbase.com>