r3615: split out struct pvfs_file_handle from struct pvfs_file. This is in

r3615: split out struct pvfs_file_handle from struct pvfs_file. This is in
preparation for adding code to pass the BASE-DENY1 and BASE-DENYDOS
tests, which require a shared filesystem handle for some specific
combinations of two DENY_DOS opens on the same connection.
(This used to be commit 6e4fdf01d19051e3923d7703dbf990fc1722b09a)