update switchlight-common

* submodules/switchlight-common d7da005...66325c2 (1):
  > Merge into master from pull request #17: arpa: Reply to ARP requests for the router IP (https://github.com/floodlight/switchlight-common/pull/17)
Merge into master from pull request #98:
update switchlight-common (https://github.com/floodlight/ivs/pull/98)