Fix python style in sql/test.

Author: kaka1992

python/pyspark/sql/tests.py

@@ -439,7 +439,7 @@ def test_rand_functions(self):
             assert row[1] >= -4.0 and row[1] <= 4.0, "got: %s" % row[1]
 
     def test_between_function(self):
-        df = self.sqlCtx.parallelize([
+        df = self.sc.parallelize([
             Row(a=1, b=2, c=3),
             Row(a=2, b=1, c=3),
             Row(a=4, b=1, c=4)]).toDF()