osd: eliminate temp collections

osd: eliminate temp collections

The temp objects have distinct pool ids.  Old temp objects are already
blown away on OSD restart.  This patch removes all the futzing with
temp_coll and puts the temp objects in the same collection as everything
else.

Interesting, collection_move_rename is now always using the same source
and dest collection.  Hmm!

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