Server access ifencrypted => "false" is treated as "true"

When a file promise in server access has
@ifencrypted => "false"@ it is regarded as "true", because the actual value is not really evaluated (just the presence of the body control).

Found in both 3.5 and 3.6 (perhaps in earlier ones, too)

Already have patch eb1612fa4309540ae , please cherry-pick or ask me to prepare a pull request (which series?)