Fix compile-fail tests by allowing double_parens.

tests/compile-fail/eq_op.rs

@@ -2,7 +2,7 @@
 #![plugin(clippy)]
 
 #[deny(eq_op)]
-#[allow(identity_op)]
+#[allow(identity_op, double_parens)]
 #[allow(no_effect, unused_variables, unnecessary_operation)]
 #[deny(nonminimal_bool)]
 fn main() {

tests/compile-fail/identity_op.rs

@@ -5,7 +5,7 @@ const ONE : i64 = 1;
 const NEG_ONE : i64 = -1;
 const ZERO : i64 = 0;
 
-#[allow(eq_op, no_effect, unnecessary_operation)]
+#[allow(eq_op, no_effect, unnecessary_operation, double_parens)]
 #[deny(identity_op)]
 fn main() {
     let x = 0;

tests/compile-fail/reference.rs

@@ -9,7 +9,7 @@ fn get_reference(n : &usize) -> &usize {
     n
 }
 
-#[allow(many_single_char_names)]
+#[allow(many_single_char_names, double_parens)]
 #[allow(unused_variables)]
 #[deny(deref_addrof)]
 fn main() {