Fix getting URL for startup commands.

qutebrowser/commands/runners.py

@@ -32,10 +32,12 @@ def replace_variables(win_id, arglist):
     args = []
     tabbed_browser = objreg.get('tabbed-browser', scope='window',
                                 window=win_id)
-    url = tabbed_browser.current_url().toString(QUrl.FullyEncoded |
-                                                QUrl.RemovePassword)
     for arg in arglist:
         if arg == '{url}':
+            # Note we have to do this in here as the user gets an error message
+            # by current_url if no URL is open yet.
+            url = tabbed_browser.current_url().toString(QUrl.FullyEncoded |
+                                                        QUrl.RemovePassword)
             args.append(url)
         else:
             args.append(arg)