OpenVSwitch QoS support

implements bp qos-ovs-qos

Change-Id: Ib0e2bed8763cbca8e75ced8b2ba57c7c548ff719
Shift TOS value by 2 bits, to reflect behavior change in OVS > 1.4.0

See

http://git.openvswitch.org/cgi-bin/gitweb.cgi?p=openvswitch;a=commit;h=cea157688977bbbb136f9c3bfe020fe485b43d39

Change-Id: I552fa49be919e7534d100942b7ccc4ac880fa5ea
Convert string value to int, then bit shift

Change-Id: Idb28ed1378f487236152f8b6113c4ebdf1662bd5
Change structure of the returned dictionary from get_policy_for_qos

Change-Id: Ifbbee062fcdd10b393b8c0cc2698f6d8532bb3ca
Remove validation code from the plugin

Change-Id: I65372eb3989d8ebf73616ca9d98d6b4ecf4ce730
Change QoS topic to singular

Change-Id: If6fa2e797c418f874e3920ef564adb6a08711df2
Pass in the 'br-ex' bridge instead of the integration bridge

Change-Id: I06650dd68bc80055646c3f0fc3b1bc7190f714a0
PEP8

Change-Id: Ic48917fbc6e542269d6aaf7a56bf2e842fd60049
Look up the segmentation_id for provider networks

Change-Id: I8009a952b0457c149962e6643502f8a822318a72
Handle Provider Networks, by using mod_flow statements

Deleting the flow based on just the dl_vlan keyword would end up
deleting multiple flows, including the flow that would handle
rewriting the VLAN tag.

Change-Id: Ia010748c084be6b8480e8a3201aa74e96ea11358