pango: disable introspection

meta-oe's pango.inc inherited gnome.bbclass which disables
gobject-introspection

error was:
| /usr/share/gir-1.0/GLib-2.0.gir:9:1: error: Unsupported version '1.1'
| /usr/share/gir-1.0/GLib-2.0.gir:9:39: error: Unsupported version '1.1'
| error parsing file Pango-1.0.gir: Failed to parse included gir GLib-2.0
| make[4]: *** [Pango-1.0.typelib] Error 1

Signed-off-by: Andreas Müller <schnitzeltony@googlemail.com>
Signed-off-by: Koen Kooi <koen@dominion.thruhere.net>