ofproto-dpif-xlate: Don't try to optimize goto table.

This patch reverts commit 5559942 (ofproto-dpif: GOTO_TABLE recursion
removal.) by reintroducing the recursion through xlate_table_action().
The main reason to do this is the introduction of new rule locking in
future patches.  The code before this patch was relatively difficult
to lock in a clean straight-forward manner.

Signed-off-by: Ethan Jackson <ethan@nicira.com>