tests: Skip queue limit tests if the queues are very large.

This should prevent timing out.

Reported-by: Andrey Korolyov <andrey@xdel.ru>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Alex Wang <alexw@nicira.com>
netflow: Correctly track flow creation time.

'created' is supposed to be the time the flow was created, but it was
getting reset to zero on every expiration, causing the flow start time to
be wonky after the first active expiration on a flow.

Reported-by: Lior Neudorfer <lior@guardicore.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
AUTHORS: Add Lior Neudorfer <lior@guardicore.com>.

Signed-off-by: Ben Pfaff <blp@nicira.com>