init-ceph: update osd crush map position on start

This is what the upstart ceph-osd.conf does; we need to do the same so that
new OSDs (e.g., that ceph-deploy creates) get added to the crush map.

Signed-off-by: Sage Weil <sage@inktank.com>
vstart.sh: use hostname instead of 'localhost' for default crush map

This matches what init-ceph, which means you can ./init-ceph ... on a
vstart cluster without changing up the crush map.

Signed-off-by: Sage Weil <sage@inktank.com>