osbs: fix race between stg and prod making registry secrets
    
    If you run these playbooks without any limit, The 4 master hosts (2
    x86_64 and 2 aarch64) will be in the play, but they all use local_action
    to make the local secrets file thats loaded. This means, whichever of
    them happens to be writing the file last, thats the version of the file
    that all 4 of them get. This is particularly bad when it's the staging
    creds and the prod hosts get it loaded. :(
    
    So, adding {{ env }} here makes the staging and prod versions seperate
    so they don't step on each other.
    
    Signed-off-by: Kevin Fenzi <kevin@scrye.com>