MT#59478 /api/ root error handling

* clear errors in Controller::API::Root::end so that they are
  not interfere with generated ones
* API::error(): add $c->stash->{is_api_error_response} = 1
  to track it in log_response()
* API::log_response(): distinguish and correctly correct errors
  for cases when is_api_response == 1 and also when there were
  $c->error('error') calls in the code, to log them correctly
  in both cases

Change-Id: Id922b8219832c1b99815d9d608309035b9b25cff

lib/NGCP/Panel/Controller/API/Root.pm

@@ -562,6 +562,7 @@ sub get_collection_properties {
 sub end : Private {
     my ($self, $c) = @_;
 
+    $c->clear_errors;
     #$self->log_response($c);
     return 1;
 }

lib/NGCP/Panel/Role/API.pm

@@ -356,6 +356,8 @@ sub error {
 
     $c->error([$message, @errors]);
 
+    $c->stash->{is_api_error_response} = 1;
+
     $c->response->content_type('application/json');
     $c->response->status($code);
     $c->response->body(JSON::to_json({ code => $code, message => $message })."\n");
@@ -1062,7 +1064,9 @@ sub log_response {
     my $rc = '';
     my $errors = '';
     if ($c->has_errors) {
-        $errors = join ', ', splice @{$c->error}, 1;
+        $errors = $c->stash->{is_api_error_response}
+                    ? join ', ', splice @{$c->error}, 1
+                    : join ', ', @{$c->error};
         $c->clear_errors;
     }
     my ($response_body, $params_data) = $self->filter_log_response(