MT#4145 Change postcode to txt, fix empty reseller

Postcodes can be alphanumeric in certain countries.

Avoid fault when editing a contact without reseller
(e.g. reseller/peer contact). You still can't save it without
setting a reseller (which might not be what we want).

lib/NGCP/Panel/Controller/Contact.pm

@@ -126,7 +126,7 @@ sub edit :Chained('base') :PathPart('edit') :Args(0) {
         $params->{reseller}{id} = $c->user->reseller_id;
     } elsif($c->user->is_superuser) {
         $form = NGCP::Panel::Form::Contact::Admin->new;
-        $params->{reseller}{id} = $c->stash->{contact}->reseller->id;
+        $params->{reseller}{id} = $c->stash->{contact}->reseller_id;
     } else {
         $form = NGCP::Panel::Form::Contact::Reseller->new;
     }

lib/NGCP/Panel/Form/Contact/Reseller.pm

@@ -41,7 +41,8 @@ has_field 'street' => (
 );
 
 has_field 'postcode' => (
-    type => 'Integer',
+    type => 'Text',
+    maxlength => 16,
 );
 
 has_field 'city' => (