init: fix typo s/{$update_crush/${update_crush/

Signed-off-by: Dietmar Maurer <dietmar@proxmox.com>
Reviewed-by: Loic Dachary <loic@dachary.org>
Merge pull request #861 from dachary/init-ceph

init: fix typo s/{$update_crush/${update_crush/
Merge git://github.com/ceph/ceph