ofproto-dpif: Mark packets as "untracked" after call to ct().

ofproto-dpif: Mark packets as "untracked" after call to ct().

Packet and Connection state is only available to the processing path
that follows the "recirc_table" argument of the ct() action.  The
previous behavior made these states available until the end of the
pipeline.  This commit changes the behavior so that the Packet and
Connection state are cleared for the current processing path whenever
ct() is called (in addition to reaching the end of the pipeline.)

A future commit will remove the behavior that a "send to controller"
action causes all packets for that flow to be handled via the slow-path.
The current behavior of connection tracking state makes that difficult
due to datapath actions containing multiple OpenFlow rules that may
contain different connection tracking states.  This change will make
that future commit possible.

Signed-off-by: Justin Pettit <jpettit@ovn.org>
Acked-by: Joe Stringer <joe@ovn.org>