ovs-ctl.in: Restore interfaces and ofports for userspace restarts.

ovs-ctl.in: Restore interfaces and ofports for userspace restarts.

When we upgrade from pre-1.9 to 1.10 or later branches, when just
the user space daemons are restarted, with the older kernel module
intact, datapaths are recreated.

This results in loosing the internal interface states like ip addresses,
routing table entries etc. Also, the 'ofport' value of the older interfaces
change.

With this patch we restore the interface states, ofport values etc,
when "ovs-ctl restart" or "/etc/init.d/openvswitch[-switch] restart
--save-flows" is called. The later command is automatically called
when debian packages are installed.

Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>