Polish previous commit

Add FunctionInspector dependency back to SimpleFunctionRegistry since we can't remove it yet to avoid backward comatibility issues

Resolves #617

spring-cloud-function-context/src/main/java/org/springframework/cloud/function/context/catalog/SimpleFunctionRegistry.java

@@ -77,7 +77,7 @@ import org.springframework.util.StringUtils;
  * @author Oleg Zhurakousky
  *
  */
-public class SimpleFunctionRegistry implements FunctionRegistry {
+public class SimpleFunctionRegistry implements FunctionRegistry, FunctionInspector {
 	protected Log logger = LogFactory.getLog(this.getClass());
 	/*
 	 * - do we care about FunctionRegistration after it's been registered? What additional value does it bring?
@@ -113,6 +113,13 @@ public class SimpleFunctionRegistry implements FunctionRegistry {
 		this.functionInvocationHelper = functionInvocationHelper;
 	}
 
+	@Override
+	public FunctionRegistration<?> getRegistration(Object function) {
+		throw new UnsupportedOperationException("FunctionInspector is deprecated. There is no need "
+				+ "to access FunctionRegistration directly since you can interogate the actual "
+				+ "looked-up function (see FunctionInvocationWrapper.");
+	}
+
 	public SimpleFunctionRegistry(ConversionService conversionService, CompositeMessageConverter messageConverter, JsonMapper jsonMapper) {
 		this(conversionService, messageConverter, jsonMapper, null);
 	}