Taking care of review comments.

 - making Ksync object next function as const funtion
 - Adding commets to Ksync changes.
 - moving ovs_tor_agent directory to same level as vxlan_agent.
 - sorting entries in lexographical order in SConscript.
Merge branch 'ovs_gw_merge' of ssh://github.com/manishsing/contrail-controller into ovs_gw_merge