govendor来管理我的项目包，但是生成的vendor文件夹包含项目本身

I have a project with folders structure:

d:/gopath/src/github.com/
              ...packages
d:/projects/src/myproject/
                       main.go
                       /submodule1/
                                  ...go files
                       /submodule2/
                                  ...go files

GOPATH is d:/gopath;d:/master

I hava import & use submodule1 and submodule2 in main.go of myproject

Then I execute command govendor init and govendor add +external to generate vendor files.

But strange things happend, I found that there is a myproject folder in the vendor folder

I have try to create a new folder named mymain to hold main.go,then try again.this time there are not any files in the folder vendor except vendor.json