client:

- Changed errno type in PosixErrorException from int to xtreemfs::pbrpc::POSIXErrno.
- FuseAdapter uses now ConvertXtreemFSErrnoToFuse() to convert XtreemFS errno to system constants.

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@2490 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534