Revert "librustc: Make unqualified identifier searches terminate at the nearest module scope. r=tjc"

This reverts commit a8d37af247.

src/libstd/c_vec.rs

@@ -40,7 +40,6 @@
 use core::libc;
 use core::oldcomm;
 use core::option;
-use core::prelude::*;
 use core::ptr;
 use core::task;
 
@@ -153,10 +152,6 @@ pub unsafe fn ptr<T>(t: CVec<T>) -> *mut T {
 
 #[cfg(test)]
 mod tests {
-    use core::prelude::*;
-
-    use c_vec::*;
-
     use core::libc::*;
     use core::libc;