Debhelper: Do not upgrade

[Jeff Bailey <jbailey@nisa.net>]

Between debhelper 3.0.26, and 3.0.31 dh_gencontrol changed, and no
longer works on the Hurd.  

I haven't filed a bug yet, because I think this is exposing a
perl-on-hurd bug (dh_gencontrol works fine under Linux).

I don't speak perl, so I might have this wrong, but:

if (-e $varname) should test for the existance of a file, yes?

perl 5.6.1-3 appears to be returning true when $varname is blank.  I get this theory because in verbose mode:

        my $substvars=pkgfile($package,"substvars");
        if (-e $substvars) {
                complex_doit("cat $substvars >> debian/${ext}substvars.debhelper");
        }

displays:

cat  >> debian/foo.substvars.debhelper

I don't know enough perl to be confident in my test case though. =( If
noone answers, I'll ask one of my coworkers, though.

Tks,
Jeff Bailey