ovs-ctl.in: Restore ofport values across force-reload-kmod.

ovs-ctl.in: Restore ofport values across force-reload-kmod.

If we want to upgrade from pre-1.10 branch to 1.10 or later
and restore flows across force-reload-kmod, we need to maintain
the value of ofport.

To do this, we fetch the value of ofport before the upgrade and use
it to populate the column 'ofport_request' after ovsdb is upgraded.
We need to do this before vswitchd is restarted as vswitchd
needs the ofport_request column populated before it starts.

Issue #13556
Signed-off-by: Gurucharan Shetty <gshetty@nicira.com>