libstd: remove field days of time::Duration and change secs to type i64

Closes rust-lang#16466.

The return type of `to_tuple_64`, `num_milliseconds` etc. has been change too, so this change is

[breaking-change]

Author: liigo

src/libstd/io/net/tcp.rs

@@ -115,7 +115,8 @@ impl TcpStream {
         let SocketAddr { ip, port } = addr;
         let addr = rtio::SocketAddr { ip: super::to_rtio(ip), port: port };
         LocalIo::maybe_raise(|io| {
-            io.tcp_connect(addr, Some(timeout.num_milliseconds() as u64)).map(TcpStream::new)
+            io.tcp_connect(addr, timeout.num_milliseconds().map(|ms| ms as u64))
+            .map(TcpStream::new)
         }).map_err(IoError::from_rtio_error)
     }
 

src/libstd/io/net/unix.rs

@@ -74,7 +74,8 @@ impl UnixStream {
         }
 
         LocalIo::maybe_raise(|io| {
-            let s = io.unix_connect(&path.to_c_str(), Some(timeout.num_milliseconds() as u64));
+            let s = io.unix_connect(&path.to_c_str(),
+                    timeout.num_milliseconds().map(|ms| ms as u64));
             s.map(|p| UnixStream { obj: p })
         }).map_err(IoError::from_rtio_error)
     }

src/libstd/io/timer.rs

@@ -25,6 +25,7 @@ use io::{IoResult, IoError};
 use kinds::Send;
 use boxed::Box;
 use rt::rtio::{IoFactory, LocalIo, RtioTimer, Callback};
+use option::Some;
 
 /// A synchronous timer object
 ///
@@ -225,9 +226,10 @@ impl Callback for TimerCallback {
 }
 
 fn in_ms_u64(d: Duration) -> u64 {
-    let ms = d.num_milliseconds();
-    if ms < 0 { return 0 };
-    return ms as u64;
+    match d.num_milliseconds() {
+        Some(ms) if ms >= 0 => ms as u64,
+        _ => 0
+    }
 }
 
 #[cfg(test)]