br100 not getting created in FlatDHCPMode

Hi,
I am currently attempting to configure OpenStack exactly as described in the following paper:
https://github.com/beloglazov/openstack-centos-kvm-glusterfs
Everythig goes fine, but once the nova network is created for VMs through issuing the command
nova-manage network create --label=public --fixed_range_v4=10.0.0.0/24 --num_networks=1 --network_size=256 --bridge=br100,
the br100 is not getting created.
Has anyone else experienced this same situation and found a solution? Please help!!
Any kind of advice/workaround would be very much appreciated.
Thanks in advance.