Explicitly export content providers

In a future version of Android, the default value for
<provider android:exported> will change from true to false.
Explicitly set android:exported="true"

Bug: 3306452
Change-Id: I18fb3f7afe37c8e463b27e05077e207b7ef13d86
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index 3d424e4..2951087 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -44,6 +44,7 @@
         <provider android:name="CalendarProvider2" android:authorities="com.android.calendar"
                 android:label="@string/provider_label"
                 android:multiprocess="false"
+                android:exported="true"
                 android:readPermission="android.permission.READ_CALENDAR"
                 android:writePermission="android.permission.WRITE_CALENDAR" />