Fix reference error in MessageReceiver from fe82e4

Fix a reference error when resolving a key conflict on an incoming end
session message. See Signal-Android/5438.

// FREEBIE

js/libtextsecure.js

@@ -37210,7 +37210,7 @@ MessageReceiver.prototype.extend({
             if ((finalMessage.flags & textsecure.protobuf.DataMessage.Flags.END_SESSION)
                     == textsecure.protobuf.DataMessage.Flags.END_SESSION &&
                     finalMessage.sync !== null) {
-                    var number = textsecure.utils.unencodeNumber(encodedNumber)[0];
+                    var number = textsecure.utils.unencodeNumber(from)[0];
                     p = this.handleEndSession(number);
             }
 

libtextsecure/message_receiver.js

@@ -311,7 +311,7 @@ MessageReceiver.prototype.extend({
             if ((finalMessage.flags & textsecure.protobuf.DataMessage.Flags.END_SESSION)
                     == textsecure.protobuf.DataMessage.Flags.END_SESSION &&
                     finalMessage.sync !== null) {
-                    var number = textsecure.utils.unencodeNumber(encodedNumber)[0];
+                    var number = textsecure.utils.unencodeNumber(from)[0];
                     p = this.handleEndSession(number);
             }