revert docs

docs/cn/bvar.md

@@ -92,4 +92,4 @@ process_username : "gejun"
 
 # bvar导出到其它监控系统格式
 
-bvar已支持的其它监控系统格式有[Prometheus](https://prometheus.io)。通过-prometheus_metrics_path可设置Prometheus的抓取url，默认路径为`/metrics`，例如brpc server跑在本机的8080端口，则在默认配置下抓取url为`127.0.0.1:8080/metrics`。
+bvar已支持的其它监控系统格式有[Prometheus](https://prometheus.io)。将Prometheus的抓取url地址的路径设置为`/brpc_prometheus_metrics`即可，例如brpc server跑在本机的8080端口，则抓取url配置为`127.0.0.1:8080/brpc_prometheus_metrics`。

docs/en/bvar.md

@@ -92,4 +92,4 @@ The monitoring system should combine data on every single machine periodically a
 
 # Dump to the format of other monitoring system
 
-Currently monitoring system supported by bvar is [Prometheus](https://prometheus.io). Flag -prometheus_metrics_path can be used to set the path of scraping target, and its default value is `/metrics`. For example, if brpc server is running on localhost:8080, the scraping target should be `127.0.0.1:8080/metrics` under default configuration.
+Currently monitoring system supported by bvar is [Prometheus](https://prometheus.io). All you need to do is to set the path in scraping target url to `/brpc_prometheus_metrics`. For example, if brpc server is running on localhost:8080, the scraping target should be `127.0.0.1:8080/brpc_prometheus_metrics`.

src/brpc/server.cpp

@@ -110,7 +110,6 @@ DEFINE_bool(enable_threads_service, false, "Enable /threads");
 
 DECLARE_int32(usercode_backup_threads);
 DECLARE_bool(usercode_in_pthread);
-DECLARE_string(prometheus_metrics_path);
 
 const int INITIAL_SERVICE_CAP = 64;
 const int INITIAL_CERT_MAP = 64;
@@ -1348,7 +1347,7 @@ int Server::AddServiceInternal(google::protobuf::Service* service,
             }
             if (sp == NULL) {
                 ServiceProperty ss =
-                    { false , SERVER_DOESNT_OWN_SERVICE, NULL, m };
+                    { false, SERVER_DOESNT_OWN_SERVICE, NULL, m };
                 _fullname_service_map[svc_name] = ss;
                 _service_map[svc_name] = ss;
                 ++_virtual_service_count;