OFStateManager: remove unused functions from utest
OFStateManager: remove "disconnected mode"

While the disconnected mode could be configured, it didn't actually have any
effect.
OFStateManager: remove max_flowtable_entries

This option had no effect.
Merge into master from pull request #171:
Remove more dead code from OFStateManager (https://github.com/floodlight/indigo/pull/171)