Make zk health indicator able to be disabled via normal properties.

Ie, use `@ConditionalOnEnabledHealthIndicator(zookeeper)`

fixes gh-101

spring-cloud-zookeeper-discovery/src/main/java/org/springframework/cloud/zookeeper/discovery/ZookeeperDiscoveryAutoConfiguration.java

@@ -19,6 +19,7 @@ package org.springframework.cloud.zookeeper.discovery;
 import org.apache.curator.framework.CuratorFramework;
 import org.apache.curator.x.discovery.ServiceDiscovery;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.actuate.autoconfigure.ConditionalOnEnabledHealthIndicator;
 import org.springframework.boot.actuate.endpoint.Endpoint;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.AutoConfigureBefore;
@@ -69,6 +70,7 @@ public class ZookeeperDiscoveryAutoConfiguration {
 	}
 
 	@Configuration
+	@ConditionalOnEnabledHealthIndicator("zookeeper")
 	@ConditionalOnClass(Endpoint.class)
 	protected static class ZookeeperDiscoveryHealthConfig {
 		@Autowired(required = false)

spring-cloud-zookeeper-discovery/src/test/java/org/springframework/cloud/zookeeper/discovery/ZookeeperDiscoveryHealthIndicatorDisabledTests.java

@@ -0,0 +1,39 @@
+package org.springframework.cloud.zookeeper.discovery;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.SpringBootConfiguration;
+import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.cloud.zookeeper.discovery.test.CommonTestConfig;
+import org.springframework.context.annotation.Import;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import static org.assertj.core.api.BDDAssertions.then;
+import static org.springframework.boot.test.context.SpringBootTest.WebEnvironment.RANDOM_PORT;
+
+/**
+ * @author Spencer Gibb
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = RANDOM_PORT,
+		properties = "management.health.zookeeper.enabled=false")
+public class ZookeeperDiscoveryHealthIndicatorDisabledTests {
+
+	@Autowired(required = false)
+	private ZookeeperDiscoveryHealthIndicator healthIndicator;
+
+	// Issue: #101 - ZookeeperDiscoveryHealthIndicator should be able to be disabled with a property
+	@Test public void healthIndicatorDisabled() {
+		// when:
+		// then:
+		then(this.healthIndicator).isNull();
+	}
+	
+	@SpringBootConfiguration
+	@EnableAutoConfiguration
+	@Import(CommonTestConfig.class)
+	static class Config {}
+
+}