Use Build.DEVICE not Build.PRODUCT.

On HTC Butterfly these match, but Build.DEVICE is actually the right value to
use.

Issue: #377

library/src/main/java/com/google/android/exoplayer/MediaCodecUtil.java

@@ -178,8 +178,8 @@ public class MediaCodecUtil {
     // Workaround an issue where creating a particular MP3 decoder on some HTC devices on platform
     // API version 16 crashes mediaserver.
     if (Util.SDK_INT == 16
-        && ("dlxu".equals(Util.PRODUCT) // HTC Butterfly
-            || "protou".equals(Util.PRODUCT)) // HTC Desire X
+        && ("dlxu".equals(Util.DEVICE) // HTC Butterfly
+            || "protou".equals(Util.DEVICE)) // HTC Desire X
         && name.equals("OMX.qcom.audio.decoder.mp3")) {
       return false;
     }

library/src/main/java/com/google/android/exoplayer/util/Util.java

@@ -62,10 +62,10 @@ public final class Util {
   public static final int SDK_INT = android.os.Build.VERSION.SDK_INT;
 
   /**
-   * Like {@link android.os.Build#PRODUCT}, but in a place where it can be conveniently overridden
+   * Like {@link android.os.Build#DEVICE}, but in a place where it can be conveniently overridden
    * for local testing.
    */
-  public static final String PRODUCT = android.os.Build.PRODUCT;
+  public static final String DEVICE = android.os.Build.DEVICE;
 
   private static final Pattern XS_DATE_TIME_PATTERN = Pattern.compile(
       "(\\d\\d\\d\\d)\\-(\\d\\d)\\-(\\d\\d)[Tt]"