NuMediaExtractor accidentally returned what looked like errors to the caller...

Change-Id: Iec0c62ba98c8a8afc5cb423a76b8f53778aeb867
related-to-bug: 6276111
diff --git a/media/libstagefright/NuMediaExtractor.cpp b/media/libstagefright/NuMediaExtractor.cpp
index a1d95e6..166a99f 100644
--- a/media/libstagefright/NuMediaExtractor.cpp
+++ b/media/libstagefright/NuMediaExtractor.cpp
@@ -429,7 +429,13 @@
 }
 
 status_t NuMediaExtractor::seekTo(int64_t timeUs) {
-    return fetchTrackSamples(timeUs);
+    ssize_t minIndex = fetchTrackSamples(timeUs);
+
+    if (minIndex < 0) {
+        return ERROR_END_OF_STREAM;
+    }
+
+    return OK;
 }
 
 status_t NuMediaExtractor::advance() {