Polish "Simplify retrieval of Narayana XARecoveryModule"

Closes gh-9725

spring-boot/src/main/java/org/springframework/boot/jta/narayana/NarayanaRecoveryManagerBean.java

 /*
- * Copyright 2012-2016 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,17 +51,19 @@ public class NarayanaRecoveryManagerBean implements InitializingBean, Disposable
 		this.recoveryManagerService.destroy();
 	}
 
-	void registerXAResourceRecoveryHelper(XAResourceRecoveryHelper xaResourceRecoveryHelper) {
+	void registerXAResourceRecoveryHelper(
+			XAResourceRecoveryHelper xaResourceRecoveryHelper) {
 		getXARecoveryModule().addXAResourceRecoveryHelper(xaResourceRecoveryHelper);
 	}
 
 	private XARecoveryModule getXARecoveryModule() {
-		XARecoveryModule xaRecoveryModule = XARecoveryModule.getRegisteredXARecoveryModule();
-		if (xaRecoveryModule == null) {
-			throw new IllegalStateException(
-					"XARecoveryModule is not registered with recovery manager");
+		XARecoveryModule xaRecoveryModule = XARecoveryModule
+				.getRegisteredXARecoveryModule();
+		if (xaRecoveryModule != null) {
+			return xaRecoveryModule;
 		}
-		return xaRecoveryModule;
+		throw new IllegalStateException(
+				"XARecoveryModule is not registered with recovery manager");
 	}
 
 }