Fix merge fallout

Author: emberian

src/libextra/ebml.rs

@@ -97,11 +97,6 @@ pub mod reader {
     use core::cast::transmute;
     use core::int;
     use core::io;
-    use core::str;
-
-    #[cfg(target_arch = "x86")]
-    #[cfg(target_arch = "x86_64")]
-    use core::ptr::offset;
 
     #[cfg(target_arch = "x86")]
     #[cfg(target_arch = "x86_64")]