selinux: change numbering of boolean directory inodes in selinuxfs

Change the numbering of the booleans directory inodes in selinuxfs to
provide more room for new inodes without a conflict in inode numbers and
to be consistent with how inode numbering is done in the
initial_contexts directory.

Signed-off-by: James Carter <jwcart2@tycho.nsa.gov>
Acked-by: Eric Paris <eparis@parisplace.org>
Acked-by: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: James Morris <jmorris@namei.org>