Apparently this code was never tested without "forks".  check-feature
returns a one-element list (0) when disabled, and assigning that to a
scalar variable made it to be called in a scalar context, which meant
my $check_forks = gitweb_check_feature("forks") were always 1!
Signed-off-by: NJunio C Hamano <junkio@cox.net>