INT-3430 AMQP Outbound: Add Eager Connect

JIRA: https://jira.spring.io/browse/INT-3430

Add an option to eagerly connect to rabbit when
only using outbound endpoints. Log an ERROR
if the connection can not be established during
context initialization.

Polishing

spring-integration-core/src/main/java/org/springframework/integration/context/IntegrationObjectSupport.java

@@ -192,6 +192,13 @@ public abstract class IntegrationObjectSupport implements BeanNameAware, NamedCo
 		return this.applicationContext == null ? null : this.applicationContext.getId();
 	}
 
+	/**
+	 * @return the applicationContext
+	 */
+	protected ApplicationContext getApplicationContext() {
+		return applicationContext;
+	}
+
 	/**
 	 * @see IntegrationContextUtils#getIntegrationProperties(BeanFactory)
 	 * @return The global integration properties.