Removed unused dependency.

Author: icmccorm

src/tools/bsan/bsan-driver/src/lib.rs

@@ -4,7 +4,6 @@
 extern crate rustc_driver;
 
 use std::env;
-use std::path::PathBuf;
 use std::sync::Arc;
 
 pub const BSAN_BUG_REPORT_URL: &str = "https://github.com/BorrowSanitizer/rust/issues/new";