Define gDevTools in network-monitor.js for the rare case where it's not already present in the environment (bug 1167655). r=vporof

toolkit/devtools/webconsole/network-monitor.js

@@ -15,6 +15,7 @@ loader.lazyImporter(this, "NetUtil", "resource://gre/modules/NetUtil.jsm");
 loader.lazyServiceGetter(this, "gActivityDistributor",
                          "@mozilla.org/network/http-activity-distributor;1",
                          "nsIHttpActivityDistributor");
+loader.lazyImporter(this, "gDevTools", "resource:///modules/devtools/gDevTools.jsm");
 
 ///////////////////////////////////////////////////////////////////////////////
 // Network logging