Add missing ExpectedException rule

Add ExpectedException rule which was missed from the 1.5.x merge.

Author: philwebb

spring-boot-project/spring-boot-tools/spring-boot-loader/src/test/java/org/springframework/boot/loader/jar/JarURLConnectionTests.java

@@ -24,6 +24,7 @@
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
+import org.junit.rules.ExpectedException;
 import org.junit.rules.TemporaryFolder;
 
 import org.springframework.boot.loader.TestJarCreator;
@@ -43,6 +44,9 @@ public class JarURLConnectionTests {
 	@Rule
 	public TemporaryFolder temporaryFolder = new TemporaryFolder(new File("target"));
 
+	@Rule
+	public ExpectedException thrown = ExpectedException.none();
+
 	private File rootJarFile;
 
 	private JarFile jarFile;