ofproto-dpif: Correct documentation of rule_dpif_lookup_from_table()

This corrects an editing error that was added by 6b83a3c5c37a0711
("ofproto: Support OF version-specific table-miss behaviours").

Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andy Zhou <azhou@nicira.com>¬