update indigo
update indigo

* submodules/indigo 655d3cd...b6b40ca (4):
  > Merge into master from pull request #164: support IPv6 in OFConnectionManager (https://github.com/floodlight/indigo/pull/164)
  > Merge into master from pull request #163: Fix bugs in logging and socket write (https://github.com/floodlight/indigo/pull/163)
  > Merge into master from pull request #162: OFStateManager: handle error return from group deletion (https://github.com/floodlight/indigo/pull/162)
  > Merge into master from pull request #161: OFConnectionManager: improve log messages (https://github.com/floodlight/indigo/pull/161)

floodlight/ivs,vezril/ivs,floodlight/ivs,floodlight/ivs,vezril/ivs,vezril/ivs