Fix deadlock in test

The test held a read lock on SETTINGS while trying to write to it. As
both happened on the same thread, that went wrong and caused a deadlock.

src/settings/mod.rs

@@ -194,21 +194,26 @@ mod tests {
         let vt2 = TypeId::of::<f32>();
         let v3: u32 = 2;
 
+        {
             settings.set(&v1);
+
             let values = settings.settings.read();
             let r1 = values.get(&vt1).unwrap().downcast_ref::<u32>().unwrap();
             assert_eq!(v1, *r1);
+        }
 
+        {
             settings.set(&v2);
-
             settings.set(&v3);
 
+            let values = settings.settings.read();
             let r2 = values.get(&vt1).unwrap().downcast_ref::<u32>().unwrap();
             let r3 = values.get(&vt2).unwrap().downcast_ref::<f32>().unwrap();
 
             assert_eq!(v3, *r2);
             assert_eq!(v2, *r3);
         }
+    }
 
     #[test]
     fn test_get() {