tanwan

**Describe the bug** When I set discovery setting in specific profile(e.g. application-test.yml), it will raise an exception. ``` java.lang.NullPointerException: null at org.springframework.cloud.config.client.ConfigServerInstanceProvider.getConfigServerInstances(ConfigServerInstanceProvider.java:57) ~[spring-cloud-config-client-3.1.0-RC1.jar:3.1.0-RC1] at org.springframework.cloud.config.client.ConfigServerInstanceMonitor.refresh(ConfigServerInstanceMonitor.java:90) ~[spring-cloud-config-client-3.1.0-RC1.jar:3.1.0-RC1] ``` The bootstrapContext register...