Don't canonicalize crate paths

Author: ChrisDenton

Diff for: compiler/rustc_metadata/src/locator.rs

@@ -432,7 +432,8 @@ impl<'a> CrateLocator<'a> {
                         if seen_paths.contains(&path) {
                             continue;
                         };
-                        seen_paths.insert(path.clone());
+                        seen_paths.insert(path);
+                        let path = spf.path.to_path_buf();
                         match kind {
                             CrateFlavor::Rlib => rlibs.insert(path, search_path.kind),
                             CrateFlavor::Rmeta => rmetas.insert(path, search_path.kind),