Remove fuchsia references as it is not supported. (#355)

tokio-tcp/src/listener.rs

@@ -234,7 +234,7 @@ impl fmt::Debug for TcpListener {
     }
 }
 
-#[cfg(all(unix, not(target_os = "fuchsia")))]
+#[cfg(unix)]
 mod sys {
     use std::os::unix::prelude::*;
     use super::TcpListener;

tokio-tcp/src/stream.rs

@@ -717,7 +717,7 @@ impl futures2::Future for ConnectFutureState {
     }
 }
 
-#[cfg(all(unix, not(target_os = "fuchsia")))]
+#[cfg(unix)]
 mod sys {
     use std::os::unix::prelude::*;
     use super::TcpStream;