SELinux: silence build warning when !CONFIG_BUG

If one builds a kernel without CONFIG_BUG there are a number of 'may be
used uninitialized' warnings.  Silence these by returning after the BUG().

Signed-off-by: Eric Paris <eparis@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>

diff --cc security/selinux/hooks.c
Simple merge

diff --cc security/selinux/netnode.c
Simple merge