Volume: Only play the new vibrate hint once per volume-down.

Bug: 18666334
Change-Id: Idfa1d0c104bb310548fde533932bffc2b41eafff
diff --git a/media/java/android/media/AudioService.java b/media/java/android/media/AudioService.java
index 03ecad2..b99b4fd 100644
--- a/media/java/android/media/AudioService.java
+++ b/media/java/android/media/AudioService.java
@@ -3110,11 +3110,12 @@
                 break;
             }
             if ((direction == AudioManager.ADJUST_LOWER)) {
-                if (VOLUME_SETS_RINGER_MODE_SILENT
-                        && mPrevVolDirection != AudioManager.ADJUST_LOWER) {
-                    ringerMode = RINGER_MODE_SILENT;
-                } else {
-                    result |= AudioManager.FLAG_SHOW_VIBRATE_HINT;
+                if (mPrevVolDirection != AudioManager.ADJUST_LOWER) {
+                    if (VOLUME_SETS_RINGER_MODE_SILENT) {
+                        ringerMode = RINGER_MODE_SILENT;
+                    } else {
+                        result |= AudioManager.FLAG_SHOW_VIBRATE_HINT;
+                    }
                 }
             } else if (direction == AudioManager.ADJUST_RAISE) {
                 ringerMode = RINGER_MODE_NORMAL;