Use AlarmManager calls to set date/time, instead of SystemClock.setTime

This way secondary users' settings app can request the system server to
set the time. Alarm driver cannot be opened as a secondary user.

Bug: 7459635
Change-Id: I1ae1630dc448021d35280a297c5d9960f8e8fc2e
diff --git a/AndroidManifest.xml b/AndroidManifest.xml
index f2e51a1..71cc520 100644
--- a/AndroidManifest.xml
+++ b/AndroidManifest.xml
@@ -61,6 +61,7 @@
     <uses-permission android:name="android.permission.MANAGE_USERS" />
     <uses-permission android:name="android.permission.READ_PROFILE" />
     <uses-permission android:name="android.permission.CONFIGURE_WIFI_DISPLAY" />
+    <uses-permission android:name="android.permission.SET_TIME" />
 
     <application android:label="@string/settings_label"
             android:icon="@mipmap/ic_launcher_settings"