Delete unused variable y in test

This fixes the errors occuring while running the ui tests

Author: infrandomness

tests/ui/needless_option_take.rs

@@ -3,5 +3,5 @@
 fn main() {
     println!("Testing option_take_on_temporary");
     let x = Some(3);
-    let y = x.as_ref().take();
+    x.as_ref().take();
 }

tests/ui/option_take_on_temporary.fixed

@@ -3,5 +3,5 @@
 fn main() {
     println!("Testing option_take_on_temporary");
     let x = Some(3);
-    let y = x.as_ref();
+    x.as_ref();
 }