ipa-server-guard: make the lock timezone aware
    
    ipa-server-guard reads a lock file in order to
    check if the lock is still taken by comparing
    the stored value, for instance:
    expire = 20230810155452589311
    with the current datetime.
    
    The expire value needs to be timezone-aware in
    order to be compared with "now" which is also tz aware.
    
    Related: https://pagure.io/freeipa/issue/9425
    
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>