apparmor: fix suspicious RCU usage warning in policy.c/policy.h

The recent 3.12 pull request for apparmor was missing a couple rcu _protected
access modifiers. Resulting in the follow suspicious RCU usage

 [   29.804534] [ INFO: suspicious RCU usage. ]
 [   29.804539] 3.11.0+ #5 Not tainted
 [   29.804541] -------------------------------
 [   29.804545] security/apparmor/include/policy.h:363 suspicious rcu_dereference_check() usage!
 [   29.804548]
 [   29.804548] other info that might help us debug this:
 [   29.804548]
 [   29.804553]
 [   29.804553] rcu_scheduler_active = 1, debug_locks = 1
 [   29.804558] 2 locks held by apparmor_parser/1268:
 [   29.804560]  #0:  (sb_writers#9){.+.+.+}, at: [<ffffffff81120a4c>] file_start_write+0x27/0x29
 [   29.804576]  #1:  (&ns->lock){+.+.+.}, at: [<ffffffff811f5d88>] aa_replace_profiles+0x166/0x57c
 [   29.804589]
 [   29.804589] stack backtrace:
 [   29.804595] CPU: 0 PID: 1268 Comm: apparmor_parser Not tainted 3.11.0+ #5
 [   29.804599] Hardware name: ASUSTeK ...