Fix 4560303: Add setting to lock later when power button pressed

This adds a feature to delay locking the device when the power button
is pressed.  This fixes a use case where the user wants to turn off
the display (e.g. to save power) but doesn't want to lock the device.

Change-Id: I711a81c3e79f7accdc1d9cb217b7806a0b8fcf63
diff --git a/res/xml/security_settings_pattern.xml b/res/xml/security_settings_pattern.xml
index 4cfc360..b91b2b6 100644
--- a/res/xml/security_settings_pattern.xml
+++ b/res/xml/security_settings_pattern.xml
@@ -39,6 +39,10 @@
             android:persistent="false"/>
 
         <CheckBoxPreference
+            android:key="power_button_instantly_locks"
+            android:title="@string/lockpattern_settings_enable_power_button_instantly_locks"/>
+
+        <CheckBoxPreference
             android:key="unlock_tactile_feedback"
             android:title="@string/lockpattern_settings_enable_tactile_feedback_title"/>