rollback some instruction for tars tracking

docs-en/tars_cpp_user_guide.md

@@ -1372,7 +1372,7 @@ Download link:
 **Instructions for use:**  
 1) Compile and install  
 The feature of tars call chain is controlled by the compile option _USE_OPENTRACKING, which is off by default.  
-Open mode: Execute export _USE_OPENTRACKING=1 in the shell before compile tars(Use \'git submodule foreach git pull origin master\' to update the sub-repository under the project before compiling).  
+Open mode: Execute export _USE_OPENTRACKING=1 in the shell before compile tars.
 After the framework is compiled, modify the \'servant/makefile/makefile.tars\' file and add a line to the front before install tars:   
 `_USE_OPENTRACKING=1`  
 to indicates that the framework has opened the call chain switch. In addition, opentraking, curl, zipkin_opentracing install path need to be manually modified to the correct path (The default path is /usr/local/lib).   

docs/tars_cpp_user_guide.md

@@ -1354,7 +1354,7 @@ Tars调用链使用了opentracking和zipkin-opentracking库，由于zipkin-opent
 使用说明：  
 1)  编译及安装  
 tars调用链功能通过编译选项_USE_OPENTRACKING进行控制，默认情况下为关闭。  
-打开方式：在shell中执行export _USE_OPENTRACKING=1，然后进行编译(编译前请使用git submodule foreach git pull origin master更新项目下的子仓库)。  
+打开方式：在shell中执行export _USE_OPENTRACKING=1，然后进行编译。  
 框架编译完后，修改servant/makefile/makefile.tars文件，在前面增加一行：  
 `_USE_OPENTRACKING=1`  
 表示框架打开了调用链开关。另外，opentraking, curl, zipkin_opentracing需要手动修改到正确的路径上来（目前默认路径为/usr/local/lib）。