Fixing handler return value

http://perl.apache.org/docs/2.0/user/handlers/intro.html#Handler_Return_Values

Hander return values are not status codes:

    $ perl -MApache2::Const -E 'say Apache2::Const::OK;'
    0
    $ perl -MApache2::Const -E 'say Apache2::Const::DECLINED;'
    -1
    $ perl -MApache2::Const -E 'say Apache2::Const::DONE;'
    -2