don't bother with most of the bad_file_ops methods

Only ->open() should be there (always failing, of course).  We never
replace ->f_op of an already opened struct file, so there's no way
for any of those methods to be called.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --cc fs/bad_inode.c
Simple merge