INT-3495 Add FileTailInChAFBean#setErrorChannel

JIRA: https://jira.spring.io/browse/INT-3495

**Cherry-pick to 4.0.x & 3.0.x**

INT-3495 Add `error-channel` to `<tail-i-c-a>`

JIRA: https://jira.spring.io/browse/INT-3495

* Fix `AbstractEndpoint` JavaDoc

spring-integration-core/src/main/java/org/springframework/integration/endpoint/AbstractEndpoint.java

@@ -124,9 +124,8 @@ public abstract class AbstractEndpoint extends IntegrationObjectSupport implemen
 	}
 
 	/**
-	 * Subclasses may override this method to invoke the callback before
-	 * or after the start behavior.
-	 * @param callback the Runnable to invoke
+	 * Stop the component and invoke callback.
+	 * @param callback the Runnable to invoke.
 	 */
 	protected void doStop(Runnable callback) {
 	    doStop();