Only run InitCommand if there is code to process

This appears to be a significant improvement in performance
(checking for the existence of init.grooy is cheap, but compiling
it is expensive).

I'm going to say this fixes gh-212.

spring-boot-cli/src/main/java/org/springframework/boot/cli/command/InitCommand.java

@@ -79,7 +79,7 @@ public class InitCommand extends OptionParsingCommand {
 					"init.groovy", "spring.groovy");
 			String[] sources = sourceOptions.getSourcesArray();
 
-			if (!(loader instanceof GroovyClassLoader)) {
+			if (!(loader instanceof GroovyClassLoader) && sources.length > 0) {
 
 				List<RepositoryConfiguration> repositoryConfiguration = RepositoryConfigurationFactory
 						.createDefaultRepositoryConfiguration();