[net] clippy: needless_update

warning: struct update has no effect, all the fields in the struct have
already been specified
   --> library/std/src/net/addr.rs:367:19
    |
367 |                 ..unsafe { mem::zeroed() }
    |                   ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `#[warn(clippy::needless_update)]` on by default
    = help: for further information visit
https://rust-lang.github.io/rust-clippy/master/index.html#needless_update

library/std/src/net/addr.rs

@@ -364,7 +364,6 @@ impl SocketAddrV6 {
                 sin6_addr: *ip.as_inner(),
                 sin6_flowinfo: flowinfo,
                 sin6_scope_id: scope_id,
-                ..unsafe { mem::zeroed() }
             },
         }
     }