Bug #368506 --> nsIMsgAccountManager.defaultAccount can throw an exception if we don't have an account, catch that in MigrateJunkMailSettings so we don't pollute the console. sr=bienvenu

mail/base/content/msgMail3PaneWindow.js

@@ -891,14 +891,16 @@ function delayedOnLoadMessenger()
 #ifdef HAVE_SHELL_SERVICE
   var nsIShellService = Components.interfaces.nsIShellService;
   var shellService;
+  var defaultAccount;
   try {
     shellService = Components.classes["@mozilla.org/mail/shell-service;1"].getService(nsIShellService);
+    defaultAccount = accountManager.defaultAccount;
   } catch (ex) {}
   
   // show the default client dialog only if we have at least one account, 
   // if we should check for the default client, 
   // and we aren't already the default for all of our recognized types (mail, news, rss)
-  if (shellService && accountManager.defaultAccount && shellService.shouldCheckDefaultClient 
+  if (shellService && defaultAccount && shellService.shouldCheckDefaultClient 
       && !shellService.isDefaultClient(true, nsIShellService.MAIL | nsIShellService.NEWS | nsIShellService.RSS))
     window.openDialog("chrome://messenger/content/defaultClientDialog.xul", "DefaultClient", 
                       "modal,centerscreen,chrome,resizable=no");
@@ -1769,7 +1771,10 @@ function MigrateJunkMailSettings()
   {
     // get the default account, check to see if we have values for our 
     // globally migrated prefs.
-    var defaultAccount = accountManager.defaultAccount;
+    var defaultAccount;
+    try {
+      defaultAccount = accountManager.defaultAccount;
+    } catch (ex) {}
     if (defaultAccount && defaultAccount.incomingServer)
     {
       // we only care about