Switch to purely namespaced enums

This breaks code that referred to variant names in the same namespace as
their enum. Reexport the variants in the old location or alter code to
refer to the new locations:

```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
=>
```
pub use self::Foo::{A, B};

pub enum Foo {
    A,
    B
}

fn main() {
    let a = A;
}
```
or
```
pub enum Foo {
    A,
    B
}

fn main() {
    let a = Foo::A;
}
```

[breaking-change]

1 files changed, 1 insertions, 0 deletions

diff --git a/src/libstd/sync/future.rs b/src/libstd/sync/future.rs
index be0af3a3f1a..e37d1f83877 100644
--- a/src/libstd/sync/future.rs
+++ b/src/libstd/sync/future.rs
@@ -29,6 +29,7 @@
 use core::prelude::*;
 use core::mem::replace;
 
+use self::FutureState::*;
 use comm::{Receiver, channel};
 use task::spawn;