Bug in new dynamic_height.jnl script

[<Russell.Fiedler@xxxxxxxxxxxxxxx>]

It looks like somebody's customised dynamic height script
has made its way into the V5.0 release.

The line

let dyn_mask = if temp[z=@nbd] eq 0 then 1

is incorrect and should be replaced with

let dyn_mask = if dyn_t[z=@nbd] eq 0 then 1


Cheers,
Russ