Ignore redundant_clone lint on test testing clone

    error: redundant clone
      --> tests/test_chain.rs:61:30
       |
    61 |     let mut chain = e.chain().clone();
       |                              ^^^^^^^^ help: remove this
       |
    note: this value is dropped without further use
      --> tests/test_chain.rs:61:21
       |
    61 |     let mut chain = e.chain().clone();
       |                     ^^^^^^^^^
       = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_clone
       = note: `-D clippy::redundant-clone` implied by `-D clippy::all`

Author: dtolnay

tests/test_chain.rs

@@ -56,6 +56,7 @@ fn test_default() {
 }
 
 #[test]
+#[allow(clippy::redundant_clone)]
 fn test_clone() {
     let e = error();
     let mut chain = e.chain().clone();