client: Made changes to the fuse_operations struct:

- Zero struct. This fixes a segmentation fault when using the client with Fuse 2.9.
- Set "flag_nullpath_ok" option.
- Set "flag_nopath" option.

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@3167 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534