DeskClock: Fix DeskClock App Crash during OTA

When Clock OTA from L to M, it's SQL DB Version maynot downgrade
from 11 to 7.

Change-Id: I0807a2cef86446afd9b5759979c3355bb404e433
CRs-Fixed: 978642
diff --git a/src/com/android/deskclock/provider/ClockDatabaseHelper.java b/src/com/android/deskclock/provider/ClockDatabaseHelper.java
index 9004471..6dd8169 100644
--- a/src/com/android/deskclock/provider/ClockDatabaseHelper.java
+++ b/src/com/android/deskclock/provider/ClockDatabaseHelper.java
@@ -137,6 +137,15 @@
     }
 
     @Override
+    public void onDowngrade(SQLiteDatabase db, int oldVersion, int currentVersion) {
+        if (oldVersion == 11 && currentVersion == 7) {
+            LogUtils.i("Downgrade from v11 to v7");
+        } else {
+            super.onDowngrade(db, oldVersion, currentVersion);
+        }
+    }
+
+    @Override
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int currentVersion) {
         LogUtils.v("Upgrading alarms database from version "
                 + oldVersion + " to " + currentVersion);