Suppress warnings about gnome_print_dialog_get_range() return type.

Suppress warnings about gnome_print_dialog_get_range() return type.

This function seems to be declared incorrectly and while it actually does
return the values we compare its return value with, it's prototyped with a
wrong enum as return type, so explicitly cast it to int to avoid warnings
from recent g++ versions.

See http://thread.gmane.org/gmane.comp.lib.wxwidgets.devel/115782/focus=115955

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@71558 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775