correct logsoftmax grad test

Author: ornithos

test/activation.jl

@@ -100,7 +100,7 @@ end
         xs = Float32[1 2 3; 1000 2000 3000]
         @test logsoftmax(xs) ≈ [-999 -1998 -2997; 0 0 0.]
 
-        @test NNlib.∇logsoftmax(ones(size(xs)), xs) ≈ zeros(Float32, size(xs))
+        @test NNlib.∇logsoftmax(ones(size(xs)), xs) ≈ Float32[1 1 1; -1 -1 -1] 
         @test NNlib.∇softmax(ones(size(xs)), xs) ≈ zeros(Float32, size(xs))
 
         # These values precalculated using PyTorch's nn.LogSoftmax