[selinux] add more rules for keygen (follow-up to 4f689743)
    
    The a396a3f8 fixed some AVCs, but many others appeared later.
    I am not exactly sure what I am doing here, I just solved the
    issues that appeard, the same way that it was done in the a396a3f8.
    
    It was necessary to do, otherwise copr-keygen failed to create
    gpg keys for new project.