SELinux: if sel_make_bools errors don't leave inconsistent state

We reset the bool names and values array to NULL, but do not reset the
number of entries in these arrays to 0.  If we error out and then get back
into this function we will walk these NULL pointers based on the belief
that they are non-zero length.

Signed-off-by: Eric Paris <eparis@redhat.com>
cc: stable@kernel.org