fuse: simplify request abort

 - don't end the request while req->locked is true

 - make unlock_request() return an error if the connection was aborted

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>

diff --cc fs/fuse/dev.c
Simple merge