title: PooledConnection has already been closed error with multiple datasources
body: <p>We're running with Grails 2.5.3 against a MySQL DB and recently introduced a second datasource definition.  We're getting the following exceptions in a non-transactional service which is calling into multiple transactional services.  The exception occurs when it tries to start the second transaction:</p>
  
  <pre><code>» 3 Aug 2016 16:49:44.119  PooledConnection has already been closed.. Stacktrace follows: 
  » 3 Aug 2016 16:49:44.119  java.sql.SQLException: PooledConnection has already been closed. 
  </code></pre>
  
  <p>It seems like Grails is closing the connection to the second datasource after the first transaction ends and is trying to reuse that connection.  I'm wondering if anyone has seen this and/or worked around it.</p>