fix issue where hash changes during dialog interaction would break things. ...

fix issue where hash changes during dialog interaction would break things.  extract relay frame id from hash at load time.  closes #295

browserid/static/dialog/resources/channel.js

@@ -113,18 +113,22 @@
     // (has window.opener) as well as whether the relay function exists.
     // If these conditions are not met, then print an appropriate message.
 
+    // get the relay here at the time the channel is setup before any navigation has
+    // occured.  if we wait the window hash might change as a side effect to user
+    // navigation, which would cause us to not find our parent window.
+    // issue #295
+    var relay = getRPRelay();
+
     function onsuccess(rv) {
       // Get the relay here so that we ensure that the calling window is still
       // open and we aren't causing a problem.
-      var relay = getRPRelay();
-      if(relay) {
+      if (relay) {
         relay(rv, null);
       }
     }
 
     function onerror(error) {
-      var relay = getRPRelay();
-      if(relay) {
+      if (relay) {
         relay(null, error);
       }
     }