servers: *Scrubber removes dead replicas and creates new ones, marks full...

servers: *Scrubber removes dead replicas and creates new ones, marks full replicas as complete if needed * client can do failover on read

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@1498 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534