servers: MRC: Changed content of xattr "xtreemfs.usable_osds": Replaced...

servers: MRC: Changed content of xattr "xtreemfs.usable_osds": Replaced canoncical hostname with address:port (where address is the configured "hostname" or the IP-Address). Now it's consistent with the information of selectable OSDs for adding a replica.

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@2745 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534