fix failure deprecation warning

Author: pietroalbini

Cargo.toml

@@ -20,7 +20,7 @@ exclude = [
 serde = "1.0"
 serde_json = "1.0"
 serde_derive = "1.0"
-failure = "0.1.1"
+failure = "0.1.2"
 log = "0.4.1"
 
 [dev-dependencies]

tests/parse_and_replace.rs

@@ -186,7 +186,7 @@ fn assert_fixtures(dir: &str, mode: &str) {
         if let Err(err) = test_rustfix_with_file(file, mode) {
             println!("failed: {}", file.display());
             warn!("{}", err);
-            for cause in err.causes().skip(1) {
+            for cause in err.iter_chain().skip(1) {
                 info!("\tcaused by: {}", cause);
             }
             failures += 1;