Fix a minor bug in SsMediaSource.

When SsMediaSource loads Manifest, it dispatches loadCompleted event even when
the load is cancelled. This change makes sure SsMediaSource dispatch
loadCancelled event instead.

GitHub: #3754

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=183241940

library/smoothstreaming/src/main/java/com/google/android/exoplayer2/source/smoothstreaming/SsMediaSource.java

@@ -485,8 +485,12 @@ public final class SsMediaSource implements MediaSource,
   @Override
   public void onLoadCanceled(ParsingLoadable<SsManifest> loadable, long elapsedRealtimeMs,
       long loadDurationMs, boolean released) {
-    eventDispatcher.loadCompleted(loadable.dataSpec, loadable.type, elapsedRealtimeMs,
-        loadDurationMs, loadable.bytesLoaded());
+    eventDispatcher.loadCanceled(
+        loadable.dataSpec,
+        loadable.type,
+        elapsedRealtimeMs,
+        loadDurationMs,
+        loadable.bytesLoaded());
   }
 
   @Override