Add r-w property of emergency number list.

Currently, the emergency calls are put into an readonly property ro.ril.ecclist.

It is possible that ecclist has to be changed before and after SIM pin lock.

And ecclist can also be changed after network broadcasts the local emgergency numbers.

So add r-w property ril.ecclist to make emergency number list changable, while still

check r-o property to make old RIL work.

telephony/java/android/telephony/PhoneNumberUtils.java

@@ -1311,7 +1311,12 @@ public class PhoneNumberUtils
         number = extractNetworkPortionAlt(number);
 
         // retrieve the list of emergency numbers
-        String numbers = SystemProperties.get("ro.ril.ecclist");
+        // check read-write ecclist property first
+        String numbers = SystemProperties.get("ril.ecclist");
+        if (TextUtils.isEmpty(numbers)) {
+            // then read-only ecclist property since old RIL only uses this
+            numbers = SystemProperties.get("ro.ril.ecclist");
+        }
 
         if (!TextUtils.isEmpty(numbers)) {
             // searches through the comma-separated list for a match,