add ext4 for hardy+1

Include ext4 in hardy+1. The stable version of ext4 is going to be in kernel 2.6.25. It has new features such as extents, support for more than 32000 subdirectorys,Nanosecond timestamps, and Faster file system checking. Extents reduce fragmentation and reduce metadata overhead. Extents also mean faster deletion on large files where ext3 takes longer than extent based filesystems such as JFS.