Fixed problem when i restart a ftth service ports because is deleting entries

app/DoctrineMigrations/Version20180221174411.php

@@ -64,7 +64,5 @@ class Version20180221174411 extends MigrationsBase
     {
         // this down() migration is auto-generated, please modify it to your needs
         $this->abortIf($this->connection->getDatabasePlatform()->getName() != 'mysql', 'Migration can only be executed safely on \'mysql\'.');
-
-        $this->addSql('DROP TABLE service_port');
     }
 }