dova: Fix value_size for struct types
dova: Fix value_size for struct types

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