bug 558340 - Fix fallback content in about:crashes when breakpad.reportURL is not set. r=mossop

toolkit/crashreporter/content/crashes.js

@@ -40,6 +40,7 @@ const Cc = Components.classes;
 const Ci = Components.interfaces;
 
 var reportsDir, pendingDir;
+var reportURL;
 
 Components.utils.import("resource://gre/modules/CrashSubmit.jsm");