Fix some Camel Jetty documentation examples

FIXME.txt

http://camel.apache.org/jetty.html

incorrect:
    <bean id="jetty" class="org.apache.camel.component.jetty.JettyHttpComponent">
        <property name="socketConnectorProperties">
            <properties>
                <property name="acceptors" value="4"/>
                <property name="maxIdleTime" value="300000"/>
            </properties>
        </property>
    </bean>

correct:
    <bean id="jetty" class="org.apache.camel.component.jetty.JettyHttpComponent">
      <property name="socketConnectorProperties">
        <map>
          <entry key="acceptors" value="4"/>
          <entry key="maxIdleTime" value="300000"/>
        </map>
      </property>
    </bean>