[DoctrineBundle] added missing entry in XSD

src/Symfony/Bundle/DoctrineBundle/Resources/config/schema/doctrine-1.0.xsd

@@ -75,6 +75,7 @@
         <xsd:attribute name="default-entity-manager" type="xsd:string" />
         <xsd:attribute name="metadata-driver" type="xsd:string" />
         <xsd:attribute name="cache-driver" type="xsd:string" />
+        <xsd:attribute name="auto-generate-proxy-classes" type="xsd:string" />
     </xsd:complexType>
 
     <xsd:complexType name="entity_managers">