mno-async_writes/client:

- Fixed problem that log messages of the form "waiting 15.0 more seconds till next attempt" contained too many digits after the decimal point.
- Better logging of retry messages if a server (i.e., a DIR) has no UUID.
- Minor cosmetic changes in log output and code.

git-svn-id: https://xtreemfs.googlecode.com/svn/branches/mno-async_writes@2969 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534