Check preKeyId isn't null in createSessionFromPreKeyWhisperMessage

Checking for falsey wouldn't catch the case where preKeyId is 0.

Author: joebandenburg

bower.json

@@ -1,7 +1,7 @@
 {
   "name": "axolotl",
   "main": "dist/axolotl.js",
-  "version": "1.2.1",
+  "version": "1.2.2",
   "authors": [
     "Joe Bandenburg <joe@bandenburg.com>"
   ],

dist/axolotl.js

@@ -1709,7 +1709,7 @@
                                 $ctx.state = 12;
                                 break;
                             case 12:
-                                $ctx.state = message.preKeyId ? 13 : 16;
+                                $ctx.state = message.preKeyId !== null ? 13 : 16;
                                 break;
                             case 13:
                                 $ctx.state = 14;

package.json

@@ -1,6 +1,6 @@
 {
   "name": "axolotl",
-  "version": "1.2.1",
+  "version": "1.2.2",
   "description": "An indepedent JavaScript implementation of Axolotl. Axolotl is a ratcheting forward secrecy protocol.",
   "main": "dist/axolotl.js",
   "directories": {

src/SessionFactory.js

@@ -113,7 +113,7 @@ function SessionFactory(crypto, store) {
         var ourSignedPreKeyPair = yield store.getLocalSignedPreKeyPair(message.signedPreKeyId);
 
         var preKeyPair;
-        if (message.preKeyId) {
+        if (message.preKeyId !== null) {
             preKeyPair = yield store.getLocalPreKeyPair(message.preKeyId);
         }