[GTK] run-webkit-tests script is failing to invoke run-launcher
https://bugs.webkit.org/show_bug.cgi?id=132051

Patch by Lorenzo Tilve <ltilve@igalia.com> on 2014-04-23
Reviewed by Philippe Normand.

After the WK1 support was dropped, if run-webkit-tests is executed
without --no-show-results parameter, the launcher is being called
using a -2 parameter that is it causing the run-launcher to break.

* Scripts/webkitpy/port/gtk.py:
(GtkPort.show_results_html_file):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@167702 268f45cc-cd09-0410-ab3c-d52691b4dbfc