Convert remaining samples to use random port

Partial fix for gh-337. See also gh-607 which complements this, but might
conflict on a merge.

spring-boot-samples/spring-boot-sample-actuator/src/test/java/sample/actuator/UnsecureSampleActuatorApplicationTests.java

@@ -48,6 +48,7 @@ public class UnsecureSampleActuatorApplicationTests {
 
 	@Value("${local.server.port}")
 	private int port;
+
 	@Test
 	public void testHome() throws Exception {
 		@SuppressWarnings("rawtypes")