debug: correct nb construction for scalar Hc

Author: franckgaga

src/controller/construct.jl

@@ -510,7 +510,7 @@ The vector is filled with `1`s, except for the last element which is `Hp - Hc +
 function move_blocking(Hp_arg::Int, Hc_arg::Int)
     Hp, Hc = Hp_arg, Hc_arg
     nb = fill(1, Hc)
-    if Hc > 1 # if Hc < 1, it will crash later with a clear error message
+    if Hc > 0 # if Hc < 1, it will crash later with a clear error message
         nb[end] = Hp - Hc + 1
     end
     return nb