gtk2 rbgtkcellrendererspin.c: drop GTK_CHECK_VERSION(2,10,0)
gtk2 rbgtkrecentmanager.c: drop GTK_CHECK_VERSION(2,10,0)
gtk2 rbgtkdrag.c: drop GTK_CHECK_VERSION(2,10,0)
gtk2 rbgtkstock.c: drop GTK_CHECK_VERSION(2,10,0)