Consul auto-registration fixes

Author: Alexander Furer

grpc-spring-boot-starter/src/main/java/org/lognet/springboot/grpc/autoconfigure/consul/ConsulGrpcAutoConfiguration.java

@@ -4,13 +4,15 @@
 import org.lognet.springboot.grpc.autoconfigure.GRpcAutoConfiguration;
 import org.springframework.boot.autoconfigure.AutoConfigureAfter;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
 import org.springframework.cloud.consul.serviceregistry.ConsulServiceRegistry;
 import org.springframework.cloud.consul.serviceregistry.ConsulServiceRegistryAutoConfiguration;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 
 @Configuration
+@ConditionalOnClass(ConsulServiceRegistry.class)
 @AutoConfigureAfter({ ConsulServiceRegistryAutoConfiguration.class, GRpcAutoConfiguration.class})
 public class ConsulGrpcAutoConfiguration{