Remove Ambiguous Subscribe Overloads with Scheduler

- Fixes ReactiveX/RxJava#1116
- These should never have been added, the subscribeOn operator already provides this functionality

language-adaptors/rxjava-scala/src/main/scala/rx/lang/scala/Observable.scala

@@ -118,17 +118,6 @@ trait Observable[+T]
     asJavaObservable.subscribe()
   }
 
-  /**
-   * $subscribeObserverMain
-   *
-   * @param observer $subscribeObserverParamObserver
-   * @param scheduler $subscribeObserverParamScheduler
-   * @return $subscribeAllReturn
-   */
-  def subscribe(observer: Observer[T], scheduler: Scheduler): Subscription = {
-    asJavaObservable.subscribe(observer.asJavaObserver, scheduler)
-  }
-
   /**
    * $subscribeObserverMain
    *
@@ -147,19 +136,6 @@ trait Observable[+T]
    */
   def apply(observer: Observer[T]): Subscription = subscribe(observer)
 
-  /**
-   * $subscribeSubscriberMain
-   *
-   * @param subscriber $subscribeSubscriberParamObserver
-   * @param scheduler $subscribeSubscriberParamScheduler
-   * @return $subscribeAllReturn
-   */
-  def subscribe(subscriber: Subscriber[T], scheduler: Scheduler): Subscription = {
-    // Add the casting to avoid compile error "ambiguous reference to overloaded definition"
-    val thisJava = asJavaObservable.asInstanceOf[rx.Observable[T]]
-    thisJava.subscribe(subscriber.asJavaSubscriber, scheduler)
-  }
-
   /**
    * $subscribeSubscriberMain
    *
@@ -220,48 +196,6 @@ trait Observable[+T]
     )
   }
 
-  /**
-   * $subscribeCallbacksMainWithNotifications
-   *
-   * @param onNext $subscribeCallbacksParamOnNext
-   * @param onError $subscribeCallbacksParamOnError
-   * @param onCompleted $subscribeCallbacksParamOnComplete
-   * @param scheduler $subscribeCallbacksParamScheduler
-   * @return $subscribeAllReturn
-   */
-  def subscribe(onNext: T => Unit, onError: Throwable => Unit, onCompleted: () => Unit, scheduler: Scheduler): Subscription = {
-    asJavaObservable.subscribe(scalaFunction1ProducingUnitToAction1(onNext),
-      scalaFunction1ProducingUnitToAction1(onError),
-      scalaFunction0ProducingUnitToAction0(onCompleted),
-      scheduler)
-  }
-
-  /**
-   * $subscribeCallbacksMainWithNotifications
-   *
-   * @param onNext $subscribeCallbacksParamOnNext
-   * @param onError $subscribeCallbacksParamOnError
-   * @param scheduler $subscribeCallbacksParamScheduler
-   * @return $subscribeAllReturn
-   */
-  def subscribe(onNext: T => Unit, onError: Throwable => Unit, scheduler: Scheduler): Subscription = {
-    asJavaObservable.subscribe(
-      scalaFunction1ProducingUnitToAction1(onNext),
-      scalaFunction1ProducingUnitToAction1(onError),
-      scheduler)
-  }
-
-  /**
-   * $subscribeCallbacksMainNoNotifications
-   *
-   * @param onNext $subscribeCallbacksParamOnNext
-   * @param scheduler $subscribeCallbacksParamScheduler
-   * @return $subscribeAllReturn
-   */
-  def subscribe(onNext: T => Unit, scheduler: Scheduler): Subscription = {
-    asJavaObservable.subscribe(scalaFunction1ProducingUnitToAction1(onNext), scheduler)
-  }
-
   /**
    * Returns a pair of a start function and an [[rx.lang.scala.Observable]] that upon calling the start function causes the source Observable to
    * push results into the specified subject.