Remove unused import

Author: Aaron1011

src/librustc_codegen_llvm/consts.rs

@@ -17,7 +17,6 @@ use rustc_codegen_ssa::traits::*;
 use syntax::symbol::{Symbol, sym};
 use syntax_pos::Span;
 use rustc::{bug, span_bug};
-use rustc_data_structures::const_cstr;
 use log::debug;
 
 use rustc::ty::layout::{self, Size, Align, LayoutOf};