Remove nightly feature

Cargo.toml

@@ -21,7 +21,6 @@ name = "test"
 path = "tests/test.rs"
 
 [features]
-nightly = []
 with-bit-vec = ["bit-vec"]
 with-chrono = ["chrono"]
 with-eui48 = ["eui48"]

src/lib.rs

@@ -41,7 +41,6 @@
 #![doc(html_root_url="https://sfackler.github.io/rust-postgres/doc/v0.11.11")]
 #![warn(missing_docs)]
 #![allow(unknown_lints, needless_lifetimes)] // for clippy
-#![cfg_attr(all(unix, feature = "nightly"), feature(unix_socket))]
 
 extern crate bufstream;
 extern crate byteorder;