Add back EnableHystrix as a courtesy

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/hystrix/EnableHystrix.java

+package org.springframework.cloud.netflix.hystrix;
+
+/**
+ * @author Spencer Gibb
+ */
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+import org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker;
+
+/**
+ * Convenience annotation for clients to enable Hystrix circuit breakers (specifically).
+ * Use this (optionally) in case you want discovery and know for sure that it is Hystrix
+ * you want. All it does is turn on circuit breakers and let the autoconfiguration find
+ * the Hystrix classes if they are available (i.e. you need Hystrix on the classpath as
+ * well).
+ * 
+ * @author Dave Syer
+ *
+ */
+@Target(ElementType.TYPE)
+@Retention(RetentionPolicy.RUNTIME)
+@Documented
+@Inherited
+@EnableCircuitBreaker
+public @interface EnableHystrix {
+}