ofproto: Add table config to struct ofproto

Add table config to to struct ofproto and set it
when a table mod message is received.

This is in preparation for changing the behaviour of the switch
based on table config.

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

---

v2
* Add OVS_EXCLUDED annotation to table_set_config().
  This was mistakenly done in a subsequent patch.
ofproto: Honour Table Mod settings for table-miss handling

This reworks lookup of rules for both table 0 and table action translation.
The result is that Table Mod settings, which can alter the miss-behaviour
of tables, including table 0, on a per-table basis may be honoured.

Previous patches proposed by myself which build on earlier merged patches
by Andy Zhou implement the ofproto side of Table Mod. So with this patch
the feature should be complete.

Neither this patch, nor any other patches it builds on, alter the default
behaviour of Open vSwitch. And in particular the OpenFlow1.1 behaviour is
the default regardless of which OpenFlow version is negotiated between the
switch and the controller.

An implementation detail, which lends itself to future work, is the
handling of OFPTC_TABLE_MISS_CONTINUE. If a table has this behaviour set by
Table Mod and a miss occurs then a loop is created, skipping to the next
table. It is quite easy to create a situation where this loop covers ~255
tables which is very expensive as the lookup for each table involves taking
locks, amongst other things.

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

---
v2
* Use ofproto->up.n_tables instead of N_TABLES as the number
  of tables present.
* Do not use the presence of rules in a table to indicate that it is
  present. Instead treat all tables, other than TBL_INTERNAL, that
  exist in ofproto.up as present. This simplifies things slightly
  and seems to be a more logical approach.
* As pointed out by Yamamoto-san
  - Read config for each table that is missed rather
    than just the first one. A logic bug that somehow I was blind to.