codegen: Remove unused variable in gtype module
codegen: Remove unused variable in gtype module

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