crush: whitespace

Signed-off-by: Sage Weil <sage@inktank.com>
crush: make item adjust weight adjust *all* instances of the item

This is useful if you have parallel trees and an item appears in both.

Return the number of items changed instead of 0; fix callers.

Signed-off-by: Sage Weil <sage@inktank.com>
crush: add test for reweighting multiple items in the tree

Signed-off-by: Sage Weil <sage@inktank.com>
Merge pull request #106 from ceph/wip-crush

crush: update weights properly for DAG (not tree) maps 

Reviewed-by: caleb miles <caleb.miles@inktank.com>