gobject-2.0: fix binding for ObjectClass.list_properties
gobject-2.0: fix binding for ObjectClass.list_properties

The array length type for the return value of
g_object_class_list_properties() is guint, not int.

Fixes GNOME Bug #592108.

Distrotech/vala,GNOME/vala,frida/vala,Distrotech/vala,Distrotech/vala,phako/vala,frida/vala,jessevdk/vala,lovebug356/vala,flobrosch/vala-fixes,GNOME/vala,flobrosch/vala-fixes,rvu95/vala,tjol/vala-tjol,kamanashisroy/aroop,tjol/vala-tjol,spidermonkdust/vala,frida/vala,playya/vala,xdave/pvala,GNOME/vala,Jc2k/vala,frida/vala,rvu95/vala,kamanashisroy/aroop,severinh/vala,spidermonkdust/vala,themiwi/vala,GNOME/vala,jessevdk/vala,severinh/vala,kamanashisroy/aroop,tjol/vala-tjol,flobrosch/vala-fixes,themiwi/vala,rvu95/vala,themiwi/vala,severinh/vala,Jc2k/vala,lovebug356/vala,playya/vala,frida/vala,playya/vala,jessevdk/vala,spidermonkdust/vala,phako/vala