错误：google-chrome-stable-44.0.2403.157-1.x86_64.rpm 的公钥没有安装
Fedora22 系统更新软件包。出现：
warning: /var/cache/dnf/google-chrome-eb0d6f10ccbdafba/packages/google-chrome-stable-44.0.2403.157-1.x86_64.rpm: Header V4 DSA/SHA1 Signature, key ID 7fac5991: NOKEY
The downloaded packages were saved in cache till the next successful transaction.
You can remove cached packages by executing 'dnf clean packages'
错误：google-chrome-stable-44.0.2403.157-1.x86_64.rpm 的公钥没有安装
主要原因是安装的google-chrome包的公钥没有安装。
解决方法：
dnf update -y --nogpgcheck
我们用选项 --nogpgcheck临时跳过包签名验证。
參考：https://ask.fedoraproject.org/en/question/31116/how-do-i-install-unsigned-packages-using-yum/