fs: fix bug preventing Finder from working.

Apparently we need to update the node's size after a write on a filehandle.
Finder stats it (the node, not the handle) while writing and complains if it's
not the right size.

Change-Id: Ie3e98328a182a4bbb3230c5190e1d57d0d3fb075
fs: set inode when statting directory permanodes

Change-Id: Ie20f02b3abab48c719a0de7b0d1409c559c5e69a