Guice will not inject properties on JndiDataSourceProvider in PrivateModules

This may be a bug in Guice.  The problem is that properties are not being injected into the JndiDataSourceProvider when it is used in a PrivateModule.  This patch fixes the issue by making an injection required on the constructor (as the other DataSource providers work).  I believe this is an acceptable change to make because the jndi.dataSource property is really a required property - it had been set as optional previously.