new MRC:

  - fixed a bug in BabuDB that could cause the MRC to crash
  - added MRC operation for OSD cleanup tool
- removed redundant import in TransferStrategies test case that caused a compile error

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@102 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534