configuration app returns non-zero value (2) if the configuration contains an error. Fixes #3031

src/core/lombok/core/configuration/ConfigurationApp.java

@@ -232,6 +232,7 @@ public class ConfigurationApp extends LombokApp {
 		if (!problems.isEmpty()) {
 			err.printf("Problems in the configuration files:%n");
 			for (String problem : problems) err.printf("- %s%n", problem);
+			return 2;
 		}
 		
 		return 0;

test/configuration/src/lombok/core/configuration/TestConfiguration.java

@@ -70,7 +70,7 @@ public class TestConfiguration {
 		
 		checkContent(directory, out, "out");
 		checkContent(directory, err, "err");
-		assertEquals(0, result);
+		assertEquals(2, result);
 	}
 
 	private void checkContent(File dir, String actual, String type) throws Exception {