fix #294 EnableCircuitBreaker error

spring-cloud-alibaba-sentinel/pom.xml

@@ -42,6 +42,12 @@
             <optional>true</optional>
         </dependency>
 
+        <dependency>
+            <groupId>org.springframework.cloud</groupId>
+            <artifactId>spring-cloud-commons</artifactId>
+            <optional>true</optional>
+        </dependency>
+
         <dependency>
             <groupId>org.springframework.cloud</groupId>
             <artifactId>spring-cloud-starter-netflix-ribbon</artifactId>

spring-cloud-alibaba-sentinel/src/main/java/org/springframework/cloud/alibaba/sentinel/custom/SentinelCircuitBreakerConfiguration.java

@@ -0,0 +1,12 @@
+package org.springframework.cloud.alibaba.sentinel.custom;
+
+import org.springframework.context.annotation.Configuration;
+
+/**
+ * @author lengleng
+ * <p>
+ * support @EnableCircuitBreaker ,Do nothing
+ */
+@Configuration
+public class SentinelCircuitBreakerConfiguration {
+}

spring-cloud-alibaba-sentinel/src/main/resources/META-INF/spring.factories

@@ -3,3 +3,6 @@ org.springframework.cloud.alibaba.sentinel.SentinelWebAutoConfiguration,\
 org.springframework.cloud.alibaba.sentinel.endpoint.SentinelEndpointAutoConfiguration,\
 org.springframework.cloud.alibaba.sentinel.custom.SentinelAutoConfiguration,\
 org.springframework.cloud.alibaba.sentinel.feign.SentinelFeignAutoConfiguration
+
+org.springframework.cloud.client.circuitbreaker.EnableCircuitBreaker=\
+org.springframework.cloud.alibaba.sentinel.custom.SentinelCircuitBreakerConfiguration