Merge pull request ReactiveX#3365 from artem-zinnatullin/code-cleanup-in-OnSubscribeRedo.RetryWithPredicate

Make field final and remove unnecessary unboxing in OnSubscribeRedo.RetryWithPredicate

Author: abersnaze

src/main/java/rx/internal/operators/OnSubscribeRedo.java

@@ -98,7 +98,7 @@ public Notification<?> call(Notification<?> terminalNotification) {
     }
 
     public static final class RetryWithPredicate implements Func1<Observable<? extends Notification<?>>, Observable<? extends Notification<?>>> {
-        private Func2<Integer, Throwable, Boolean> predicate;
+        private final Func2<Integer, Throwable, Boolean> predicate;
 
         public RetryWithPredicate(Func2<Integer, Throwable, Boolean> predicate) {
             this.predicate = predicate;