Support for Jmx (and Integration) autoconfig in parent contexts

When there are parent contexts we already had a strategy for registering
the actuator endpoints, but not the regular JMX or Integration MBeans.
This chnage makes the autoconfigs for JMX aware of the parent context.

Also adds a sample with a parent context.

See gh-847

spring-boot-samples/spring-boot-sample-parent-context/src/main/resources/application.properties

@@ -0,0 +1 @@
+service.greeting: Hello

spring-boot-samples/spring-boot-sample-parent-context/src/main/resources/integration-context.xml

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<beans xmlns="http://www.springframework.org/schema/beans"
+	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xmlns:int="http://www.springframework.org/schema/integration"
+	xmlns:int-file="http://www.springframework.org/schema/integration/file"
+	xsi:schemaLocation="http://www.springframework.org/schema/integration http://www.springframework.org/schema/integration/spring-integration.xsd
+		http://www.springframework.org/schema/integration/file http://www.springframework.org/schema/integration/file/spring-integration-file.xsd
+		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">
+
+	<int-file:inbound-channel-adapter channel="input" directory="target/input" filename-pattern="*">
+		<int:poller fixed-rate="500"/>
+	</int-file:inbound-channel-adapter>
+
+	<int:service-activator input-channel="input" ref="sampleEndpoint" output-channel="output"/>
+
+	<int:channel id="output"/>
+
+	<int-file:outbound-channel-adapter channel="output" directory="target/output"/>
+
+</beans>

spring-boot-samples/spring-boot-sample-parent-context/src/main/resources/logback.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<configuration>
+	<include resource="org/springframework/boot/logging/logback/base.xml"/>	
+
+	<logger name="org.springframework.integration.file" level="DEBUG" />
+</configuration>