Correct IoStream::set_keepalive for UDS (actix#564)

Enable uds feature in tests

.travis.yml

@@ -35,7 +35,7 @@ script:
     cargo check --features rust-tls
     cargo check --features ssl
     cargo check --features tls
-    cargo test --features="ssl,tls,rust-tls" -- --nocapture
+    cargo test --features="ssl,tls,rust-tls,uds" -- --nocapture
     fi
   - |
     if [[ "$TRAVIS_RUST_VERSION" == "nightly" ]]; then

src/server/mod.rs

@@ -334,7 +334,7 @@ impl IoStream for ::tokio_uds::UnixStream {
     }
 
     #[inline]
-    fn set_keepalive(&mut self, _nodelay: bool) -> io::Result<()> {
+    fn set_keepalive(&mut self, _dur: Option<time::Duration>) -> io::Result<()> {
         Ok(())
     }
 }