contextParentBean.voidLookup() to hack #8.

allows to import in root context and has single bean with this class for autowiring
it might sense to move all bs xml schema to it.

   <bean id="clinicServiceVoid"
      factory-bean="root"
      factory-method="voidLookup">
     <constructor-arg value="clinicService"/>
     <constructor-arg value="org.springframework.samples.petclinic.service.ClinicService"/>
   </bean>