giomodule: return a copy of module name
giomodule: return a copy of module name

This is a regression from commit 6dedc0.

The clients expect to free the received module name, so the function
must return a copy.

https://bugzilla.gnome.org/show_bug.cgi?id=756952

Distrotech/glib,MathieuDuponchelle/glib,MathieuDuponchelle/glib,mzabaluev/glib,ieei/glib,MathieuDuponchelle/glib,johne53/MB3Glib,endlessm/glib,endlessm/glib,johne53/MB3Glib,MathieuDuponchelle/glib,Distrotech/glib,johne53/MB3Glib,mzabaluev/glib,endlessm/glib,mzabaluev/glib,Distrotech/glib,mzabaluev/glib,johne53/MB3Glib,Distrotech/glib,mzabaluev/glib,ieei/glib,johne53/MB3Glib,johne53/MB3Glib,endlessm/glib,ieei/glib,MathieuDuponchelle/glib,Distrotech/glib,ieei/glib,ieei/glib,endlessm/glib