remove failing test

Previously I planned to force chunksize value to be larger than 2 and wrote a test to allow chunksize equal to two.
Fold takes a combination function which I am not sure how to interpret and prefer not to mess with so if the user choses a chunksize of 1 than we raise an exception instead of trapping ourselves in an infinite loop.

Author: medecau

toolz/sandbox/tests/test_parallel.py

@@ -13,7 +13,6 @@ def test_fold():
     assert fold(add, range(10), 0) == reduce(add, range(10), 0)
     assert fold(add, range(10), 0, map=Pool().map) == reduce(add, range(10), 0)
     assert fold(add, range(10), 0, chunksize=2) == reduce(add, range(10), 0)
-    assert fold(add, range(10), 0, chunksize=1) == reduce(add, range(10), 0)
     assert fold(add, range(10)) == fold(add, range(10), 0)
 
     def setadd(s, item):