XML ref to bean

Spring 5 removes ref XML attribute in favor of bean XML attribute. This
commit updates all the samples and tests to use bean instead of ref.

Issue gh-4080

samples/xml/contacts/client/clientContext.xml

@@ -23,7 +23,7 @@
 			<value>rmi://${serverName}:${rmiPort}/contactManager</value>
 		</property>
 		<property name="remoteInvocationFactory">
-			<ref local="remoteInvocationFactory"/>
+			<ref bean="remoteInvocationFactory"/>
 		</property>
 	</bean>
 
@@ -40,7 +40,7 @@
 			<value>http://${serverName}:${httpPort}${contextPath}/remoting/ContactManager-httpinvoker</value>
 		</property>
 		<property name="httpInvokerRequestExecutor">
-			<ref local="httpInvokerRequestExecutor"/>
+			<ref bean="httpInvokerRequestExecutor"/>
 		</property>
 	</bean>