title: Bulk update with datanucleus errors out
body: <p>I'm trying to use the JDOQL bulk update in datanucleus, but I get the following exception,</p>
  
  <p>12/08/13 13:06:56 INFO DataNucleus.Persistence: Property datanucleus.cache.level2 unknown - will be ignored
  12/08/13 13:06:56 INFO DataNucleus.Persistence: ================= Persistence Configuration ===============
  12/08/13 13:06:56 INFO DataNucleus.Persistence: DataNucleus Persistence Factory - Vendor: "DataNucleus"  Version: "2.2.5"
  12/08/13 13:06:56 INFO DataNucleus.Persistence: DataNucleus Persistence Factory initialised for datastore URL="jdbc:derby:;databaseName=metastore_db;create=true" driver="org.apache.derby.jdbc.EmbeddedDriver" userName="APP"
  12/08/13 13:06:56 INFO DataNucleus.Persistence: ===========================================================
  12/08/13 13:06:57 INFO Datastore.Schema: Initialising Catalog "", Schema "APP" using "None" auto-start option
  12/08/13 13:06:57 INFO Datastore.Schema: Catalog "", Schema "APP" initialised - managing 0 classes
  12/08/13 13:06:57 INFO DataNucleus.MetaData: Registering listener for metadata initialisation</p>
  
  <p>Query to be executed: UPDATE myDomain.MTable t SET t.tableName = 'tmp3' WHERE t.tableName == 'tmp'
  12/08/13 13:06:57 INFO DataNucleus.JDO: Exception thrown
  JPQL UPDATE query has no update clause! Query should be like "UPDATE Entity e SET e.param = new_value WHERE [where-clause]"
  org.datanucleus.exceptions.NucleusUserException: JPQL UPDATE query has no update clause! Query should be like "UPDATE Entity e SET e.param = new_value WHERE [where-clause]"
      at org.datanucleus.query.JDOQLSingleStringParser$Compiler.compileUpdate(JDOQLSingleStringParser.java:236)
      at org.datanucleus.query.JDOQLSingleStringParser$Compiler.compileSelect(JDOQLSingleStringParser.java:160)
      at org.datanucleus.query.JDOQLSingleStringParser$Compiler.compile(JDOQLSingleStringParser.java:125)
      at org.datanucleus.query.JDOQLSingleStringParser$Compiler.access$000(JDOQLSingleStringParser.java:114)
      at org.datanucleus.query.JDOQLSingleStringParser.parse(JDOQLSingleStringParser.java:106)
      at org.datanucleus.store.query.AbstractJDOQLQuery.(AbstractJDOQLQuery.java:108)
      at org.datanucleus.store.rdbms.query.JDOQLQuery.(JDOQLQuery.java:119)
      at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
      at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
      at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
      at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
      at org.datanucleus.plugin.NonManagedPluginRegistry.createExecutableExtension(NonManagedPluginRegistry.java:597)
      at org.datanucleus.plugin.PluginManager.createExecutableExtension(PluginManager.java:324)
      at org.datanucleus.store.query.QueryManager.newQuery(QueryManager.java:264)
      at org.datanucleus.jdo.JDOPersistenceManager.newQuery(JDOPersistenceManager.java:1272)</p>
  
  <p>I'm using DN-core-2.2.4, DN-RDBMS-2.2.4, DN-Enhancer-2.1.3 and DN-ConnectionPool-2.0.3.</p>
  
  <p>The code snippet that I fires the update is as follows,</p>
  
  <pre><code>openTransaction();
  Query q = pm.newQuery("javax.jdo.query.JDOQL", query);
  q.compile();
  Collection&lt;?&gt; result = (Collection&lt;?&gt;) q.execute();
  committed = commitTransaction();
  </code></pre>
  
  <p>Any pointers on what I'm doing wrong.</p>
  
  <p>My query is of the form "UPDATE myDomain.A t SET t.tableName = 'tmp3' WHERE t.tableName == 'tmp'"</p>