Remove closure-execution from OptionHandler

It seems that the code for executing a groovy closure from the
OptionHandler is never executed and therefore not needed.

Removing the code gives the benefit that the Groovy-classes are not
needed if someone else wants to use the spring-boot-cli infrastructure to
run his own cli interface.

Closes gh-4411

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

@@ -29,7 +29,6 @@ import java.util.Map;
 import java.util.Set;
 import java.util.TreeSet;
 
-import groovy.lang.Closure;
 import joptsimple.BuiltinHelpFormatter;
 import joptsimple.HelpFormatter;
 import joptsimple.OptionDescriptor;
@@ -51,8 +50,6 @@ public class OptionHandler {
 
 	private OptionParser parser;
 
-	private Closure<?> closure;
-
 	private String help;
 
 	private Collection<OptionHelp> optionHelp;
@@ -76,10 +73,6 @@ public class OptionHandler {
 	protected void options() {
 	}
 
-	public void setClosure(Closure<?> closure) {
-		this.closure = closure;
-	}
-
 	public final ExitStatus run(String... args) throws Exception {
 		String[] argsToUse = args.clone();
 		for (int i = 0; i < argsToUse.length; i++) {
@@ -98,18 +91,6 @@ public class OptionHandler {
 	 * @throws Exception in case of errors
 	 */
 	protected ExitStatus run(OptionSet options) throws Exception {
-		if (this.closure != null) {
-			Object result = this.closure.call(options);
-			if (result instanceof ExitStatus) {
-				return (ExitStatus) result;
-			}
-			if (result instanceof Boolean) {
-				return (Boolean) result ? ExitStatus.OK : ExitStatus.ERROR;
-			}
-			if (result instanceof Integer) {
-				return new ExitStatus((Integer) result, "Finished");
-			}
-		}
 		return ExitStatus.OK;
 	}