Remove the agent_scheduler from supported_extension_alias
in the OVS plugin

Change-Id: I6d0e5e241d27924289842419afa0e47e30bc8f8d
Signed-off-by: Rosario Di Somma <rosario.disomma@dreamhost.com>
Merge pull request #18 from rodis/fix/remove_agent_scheduler

Remove the agent_scheduler from supported_extension_alias