floodlight make the VMs can not getDHCP IP address

I used the floodlight as the openflow controller in openstack. in the compute node ,I use the command "set-controller IP:port" to set the floodlight address as the ovs bridge br-int's controller. but when I typed the command,I found the OVS flow tables were flushed,the flow rules were deleted . So when I created a VM,the VM could not get the DHCP IP address,my Openstack is Grizzly vlan mode,I found the DHCP reply from network node could not recived by VM.
 Does you have the same problem? Does floodlight can be used in OPENSTACk as the openvswitch's controller? I used the floodlight to get the virtual network topology.

before I set the controller ,the OVS flow table is like this:
[root@node8 ~]# ovs-ofctl dump-flows br-int
NXST_FLOW reply (xid=0x4):
 cookie=0x0, duration=52.074s, table=0, n_packets=11, n_bytes=1430, idle_age=15, priority=3,in_port=29,dl_vlan=1000 actions=mod_vlan_vid:8,NORMAL
 cookie=0x0, duration=307.365s, table=0, n_packets=8123, n_bytes=728475, idle_age=0, priority=0 actions=NORMAL

[root@node8 ~]# ovs-vsctl show
3fa12857-c008-451f-a6f3-70cf30d1b92e
    Bridge br-int
        Port "qvoab109943-af"
            tag: 8
            Interface "qvoab109943-af"
        Port br-int
            Interface br-int
                type: internal
        Port "int-br-eth1"
            Interface "int-br-eth1"
    Bridge "br-eth1"
        Port "eth1"
            Interface "eth1"
        Port "phy-br-eth1"
            Interface "phy-br-eth1"
        Port "br-eth1"
            Interface "br-eth1"
                type: internal
    ovs_version: "1.7.1"

but after I set the controller,the flow tables is like this:

[root@node8 ~]# ovs-ofctl dump-flows br-int
NXST_FLOW reply (xid=0x4):

[root@node8 ~]# ovs-vsctl show
3fa12857-c008-451f-a6f3-70cf30d1b92e
    Bridge br-int
        Controller "tcp:10.0.0.7"
            is_connected: true
        Port "qvoab109943-af"
            tag: 8
            Interface "qvoab109943-af"
        Port br-int
            Interface br-int
                type: internal
        Port "int-br-eth1"
            Interface "int-br-eth1"
    Bridge "br-eth1"
        Port "eth1"
            Interface "eth1"
        Port "phy-br-eth1"
            Interface "phy-br-eth1"
        Port "br-eth1"
            Interface "br-eth1"
                type: internal
    ovs_version: "1.7.1"