fuse: request_end(): do once
fuse: request_end(): do once

When the connection is aborted it is possible that request_end() will be
called twice.  Use atomic test and set to do the actual ending only once.

test_and_set_bit() also provides the necessary barrier semantics so no
explicit smp_wmb() is necessary.

Signed-off-by: Miklos Szeredi <84cd5483a2f9acd1c37251cba7c2908448f221b8@suse.cz>
Reviewed-by: Ashish Samant <8b81d500fde961aeb6e5c1b881cda93a1c7f3f60@oracle.com>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs