xfs_io: Document shutdown -f

Add help and manpage information for xfs_io shutdown -f

[sandeen: further text editing]

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>

2 files changed