修改ubuntu系统语言

中文：

1. gedit /etc/default/locale
     LANG="zh_CN.UTF-8"
     LANGUAGE="zh_CN:zh"
2. gedit ~/.pam_environment
    LANG=zh_CN.UTF-8
    LANGUAGE=zh_CN:zh

英文：

1. gedit /etc/default/locale
     LANG="en_US.UTF-8"
     LANGUAGE="en_US:en"
2. gedit ~/.pam_environment
    LANG=en_US.UTF-8
    LANGUAGE=en_US:en