Use connection keep-alive
    
    Do not forcefully close the connection after every request. This enables
    HTTP connection keep-alive, also known as persistent TCP and TLS/SSL
    connection. Keep-alive speed up consecutive HTTP requests by 15% (for
    local, low-latency network connections to a fast server) to multiple
    times (high latency connections or remote peers).
    
    https://pagure.io/freeipa/issue/6641
    
    Signed-off-by: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Tomas Krizek <tkrizek@redhat.com>