ofproto: Inline actions in struct rule_actions.

ofproto: Inline actions in struct rule_actions.

Allocate struct rule_actions and the space for the actions at once.
This reduces one memory indirection and helps reduce cache misses
visible in perf annotations.

Fix some old comments referring to ref count, since we now use RCU for
this.

Enforce constness of the actions that are assigned from rule_actions
throughout the code.

Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>