Fix issue 2097083: STREAM_SYSTEM should be at max volume.

Changed default volume for STREAM_SYSTEM and STREAM_SYSTEM_ENFORCED to the maximum value.

media/java/android/media/AudioManager.java

@@ -156,13 +156,13 @@ public class AudioManager {
     /**  @hide Default volume index values for audio streams */
     public static final int[] DEFAULT_STREAM_VOLUME = new int[] {
         4,  // STREAM_VOICE_CALL
-        5,  // STREAM_SYSTEM
+        7,  // STREAM_SYSTEM
         5,  // STREAM_RING
         11, // STREAM_MUSIC
         6,  // STREAM_ALARM
         5,  // STREAM_NOTIFICATION
         7,  // STREAM_BLUETOOTH_SCO
-        5,  // STREAM_SYSTEM_ENFORCED
+        7,  // STREAM_SYSTEM_ENFORCED
         11, // STREAM_DTMF
         11  // STREAM_TTS
     };