Correctly identify customer contracts

the product handle was compared to the class name by mistake

lib/NGCP/Panel/Controller/Contract.pm

@@ -138,9 +138,9 @@ sub base :Chained('contract_list') :PathPart('') :CaptureArgs(1) {
 
     my $billing_mapping = $res->billing_mappings->find($res->get_column('bmid'));
     if (! defined ($billing_mapping->product) || (
-        $billing_mapping->product->handle ne 'reseller' &&
-        $billing_mapping->product->handle ne 'sippeering' &&
-        $billing_mapping->product->handle ne 'pstnpeering')) {
+        $billing_mapping->product->handle ne 'VOIP_RESELLER' &&
+        $billing_mapping->product->handle ne 'SIP_PEERING' &&
+        $billing_mapping->product->handle ne 'PSTN_PEERING')) {
 
         $c->stash(page_title => "Customer",
                   page_title_plural => "Customers");