title: "The task 'generate-sql' has not been registered", when executing php symfony doctrine:build --sql
body: <p>I tried adding new entities to my project (Symfony 1.4) and I got the <code>The task 'generate-sql' has not been registered</code> error when executing <code>php symfony doctrine:build --sql</code>.
  The command <code>php symfony doctrine:build --model</code> executed without errors and the classes were built.<br>
  Previously the <code>build-sql</code> command was working, I suspect that may be some file is corrupt or missing, there was some file movement between computers involved... </p>
  
  <p>I guess my question is - how to ensure that the task is properly registered?<br>
  I have looked in the project files but I cannot yet understand where the connection between <code>'generate-sql'</code> in <code>sfDoctrineBuildSqlTask::execute</code> and <code>Doctrine_Task_GenerateSql::execute</code> is established.</p>