pwpolicy: change lifetime error message
    
    ipa pwpolicy-mod --minlife $min --maxlife $max
    accepts $max >= $min, yet the error message says:
    "Maximum password life must be greater than minimum."
    
    Change the error message so that it conveys the
    actual logic.
    
    Fixes: https://pagure.io/freeipa/issue/9038
    Signed-off-by: François Cami <fcami@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>