apparmor: Fix logical error in verify_header()

verify_header() is currently checking whether interface version is less
than 5 *and* greater than 7, which always evaluates to false. Instead it
should check whether it is less than 5 *or* greater than 7.

Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>