Originating flag not set correctly when using milter/AM.PDP

When using AM.PDP requests (like amavisd-milter) and no policy bank is used, originating flag is left as default (1) and all mail is considered local. Similar fix as Issue #6 (closed).

--- amavisd-2.12.0.orig 2019-07-25 17:19:11.000000000 +0300
+++ amavisd     2020-04-22 14:14:32.568135191 +0300
@@ -21854,6 +21854,7 @@
     Amavis::load_policy_bank($_,$msginfo) for @bank_names_cl;
     # additional banks from the request
     Amavis::load_policy_bank(untaint($_),$msginfo) for @$bank_names_ref;
+    $msginfo->originating(c('originating'));
     my $sender = $msginfo->sender;
     if (defined $policy_bank{'MYUSERS'} &&
         $sender ne '' && $msginfo->originating &&