girparser: Add sentinel metadata argument
girparser: Add sentinel metadata argument

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