hack to prevent sort ascending flag issue (seen in CI)

Author: Ehsan Totoni

hpat/hiframes/sort.py

@@ -46,6 +46,10 @@ def __init__(self, df_in, df_out, key_arrs, out_key_arrs, df_in_vars,
         self.df_in_vars = df_in_vars
         self.df_out_vars = df_out_vars
         self.inplace = inplace
+        # HACK make sure ascending is boolean (seen error for none in CI)
+        # TODO: fix source of issue
+        if not isinstance(ascending, bool):
+            ascending = True
         self.ascending = ascending
         self.loc = loc