apparmor: localize getting the security context to a few macros

Signed-off-by: John Johansen <john.johansen@canonical.com>
Acked-by: Seth Arnold <seth.arnold@canonical.com>

diff --cc security/apparmor/context.c
Simple merge

diff --cc security/apparmor/domain.c
Simple merge

diff --cc security/apparmor/include/context.h
Simple merge

diff --cc security/apparmor/lsm.c
Simple merge