Add "locked" column to sms and pdu tables.

A user can lock an SMS message and prevent it from being auto-deleted.
diff --git a/core/java/android/provider/Telephony.java b/core/java/android/provider/Telephony.java
index 4078fa6..a2c253a 100644
--- a/core/java/android/provider/Telephony.java
+++ b/core/java/android/provider/Telephony.java
@@ -146,7 +146,13 @@
          * <P>Type: TEXT</P>
          */
         public static final String SERVICE_CENTER = "service_center";
-    }
+
+        /**
+         * Has the message been locked?
+         * <P>Type: INTEGER (boolean)</P>
+         */
+        public static final String LOCKED = "locked";
+}
 
     /**
      * Contains all text based SMS messages.
@@ -1008,6 +1014,12 @@
          * <P>Type: INTEGER</P>
          */
         public static final String THREAD_ID = "thread_id";
+
+        /**
+         * Has the message been locked?
+         * <P>Type: INTEGER (boolean)</P>
+         */
+        public static final String LOCKED = "locked";
     }
 
     /**