Dokan:  fall back to calling isdir() if st_mode doesn't contain enough info.
Dokan:  fall back to calling isdir() if st_mode doesn't contain enough info.

This avoid causing breakage when the filesystem has specific permission bits
but no type bits in st_mode; fixes issue #45


git-svn-id: 74b2def6592cf29d88d1a5d33b5c4a2732d8507c@503 67cdc799-7952-0410-af00-57a81ceafa0f

pombreda/pyfilesystem-4