Fix concat' test on node 0.10

Author: hdgarrood

test/Main.purs

@@ -116,10 +116,10 @@ testFill = do
 testConcat' :: Test
 testConcat' = do
   bufs <- traverse fromArray $ map (\x -> [x, x+1, x+2]) [0,3,6,9,12]
-  buf  <- concat' bufs 10
+  buf  <- concat' bufs 15
   out  <- toArray buf
 
-  assertEq [0,1,2,3,4,5,6,7,8,9] out
+  assertEq [0,1,2,3,4,5,6,7,8,9,10,11,12,13,14] out
 
 assertEq :: forall a. (Eq a, Show a) => a -> a -> Test
 assertEq x y =