GVariant binding: bind g_variant_{get,new}_va
GVariant binding: bind g_variant_{get,new}_va

I didn't bind these because I didn't know that it was possible to use
va_list from Vala.  It is, so bind them.

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