MediaMetadataRetrieverTest: remove unused import to fix compile error.

Bug: 24623447
Change-Id: I9769b641f6e45df7b17f04b7598443225889feea
diff --git a/tests/tests/security/src/android/security/cts/MediaMetadataRetrieverTest.java b/tests/tests/security/src/android/security/cts/MediaMetadataRetrieverTest.java
index 6557965..06ef5fd 100644
--- a/tests/tests/security/src/android/security/cts/MediaMetadataRetrieverTest.java
+++ b/tests/tests/security/src/android/security/cts/MediaMetadataRetrieverTest.java
@@ -20,7 +20,6 @@
 
 import android.content.res.AssetFileDescriptor;
 import android.content.res.Resources;
-import android.cts.util.MediaUtils;
 import android.media.MediaMetadataRetriever;
 import android.test.AndroidTestCase;