rename MySelfCert.cer to rootsign.cer
重命名MySelfCert.cer为rootsign.cer

Signed-off-by: Wanpeng Song <swpustc@mail.ustc.edu.cn>
fix .gitignore file
修正.gitignore文件

Signed-off-by: Wanpeng Song <swpustc@mail.ustc.edu.cn>
new filename: rootcert.cer
新文件名：rootcert.cer

Signed-off-by: Wanpeng Song <swpustc@mail.ustc.edu.cn>
change self sign cert file name to rootcert
修改自签名证书名为rootcert

Signed-off-by: Wanpeng Song <swpustc@mail.ustc.edu.cn>