prevent crash when app.id is not set

apollo-client/src/main/java/com/ctrip/framework/apollo/internals/RemoteConfigRepository.java

@@ -259,6 +259,7 @@ public class RemoteConfigRepository extends AbstractConfigRepository {
   }
 
   private void scheduleLongPollingRefresh() {
+    try {
       final String appId = m_configUtil.getAppId();
       final String cluster = m_configUtil.getCluster();
       final String dataCenter = m_configUtil.getDataCenter();
@@ -268,6 +269,12 @@ public class RemoteConfigRepository extends AbstractConfigRepository {
           doLongPollingRefresh(appId, cluster, dataCenter);
         }
       });
+    } catch (Throwable ex) {
+      ApolloConfigException exception =
+          new ApolloConfigException("Schedule long polling refresh failed", ex);
+      Cat.logError(exception);
+      logger.warn(ExceptionUtil.getDetailMessage(exception));
+    }
   }
 
   private void doLongPollingRefresh(String appId, String cluster, String dataCenter) {