try gpg2 and fall back to gpg
try gpg2 and fall back to gpg

resolves #1976

juhp/stack,sjakobi/stack,phadej/stack,AndreasPK/stack,Fuuzetsu/stack,Fuuzetsu/stack,anton-dessiatov/stack,martin-kolinek/stack,juhp/stack,Heather/stack,AndrewRademacher/stack,Heather/stack,Blaisorblade/stack,Blaisorblade/stack,deech/stack,deech/stack,AndrewRademacher/stack,phadej/stack,mrkkrp/stack,MichielDerhaeg/stack,sjakobi/stack,martin-kolinek/stack,MichielDerhaeg/stack,AndreasPK/stack,mrkkrp/stack,anton-dessiatov/stack