base/deb: bump 'system' users limit beyond Kolla ones
base/deb: bump 'system' users limit beyond Kolla ones

Haproxy complains that user 'haproxy' already exists during installation
and is not 'system user'. So let bump range for 'system' users to make
it happier.

Our images do not have normal users so it should not affect.

Change-Id: Ia073774c8053111652847a39d80665fd9d3e5dcf

openstack/kolla,stackforge/kolla,rahulunair/kolla,openstack/kolla,rahulunair/kolla,stackforge/kolla,stackforge/kolla