title: Glide listener doesn't work
body: <p>I'm using Glide to load images and I added a listener to know when resource is ready or if there was an error of any type:</p>
  
  <pre><code>Glide.with(mContext)
      .load(url)
      .placeholder(R.drawable.glide_placeholder)
      // use dontAnimate and not crossFade to avoid a bug with custom views
      .dontAnimate()
      .diskCacheStrategy(DiskCacheStrategy.ALL)
      .listener(new RequestListener&lt;String, GlideDrawable&gt;() {
          @Override
          public boolean onException(Exception e, String model, Target&lt;GlideDrawable&gt; target, boolean isFirstResource) {
              // do something
              return true;
          }
  
          @Override
          public boolean onResourceReady(GlideDrawable resource, String model, Target&lt;GlideDrawable&gt; target, boolean isFromMemoryCache, boolean isFirstResource) {
              // do something
              return true;
           }
      })
      .into(mCustomImageView);
  </code></pre>
  
  <p>The app never runs inside <code>onResourceReady</code> or <code>onException</code> but if I remove the listener and let the async download without a callback, it runs correctly:</p>
  
  <pre><code>Glide.with(mContext)
      .load(url)
      .placeholder(R.drawable.glide_placeholder)
      // use dontAnimate and not crossFade to avoid a bug with custom views
      .dontAnimate()
      .diskCacheStrategy(DiskCacheStrategy.ALL)
      .into(mCustomImageView);
  </code></pre>
  
  <p>I tried also with <code>GlideDrawableImageViewTarget</code> instead of listener to receive callbacks but app runs inside <code>onLoadStarted</code> but never runs inside <code>onLoadCleared</code>, <code>onLoadFailed</code> and <code>onResourceReady</code>.</p>