TST: also skip datetime_NaT tests for sqlite3

- tests were failing on some combination of platform/version, see #7100, so skip for now until real solution is implemented

Author: jorisvandenbossche

pandas/io/tests/test_sql.py

@@ -902,6 +902,8 @@ def test_datetime_NaT(self):
             raise nose.SkipTest('writing datetime not working with pymysql')
         if self.driver == 'psycopg2':
             raise nose.SkipTest('writing datetime NaT not working with psycopg2')
+        if self.flavor == 'sqlite':
+            raise nose.SkipTest('reading datetime NaT not working with sqlite')
 
         df = DataFrame({'A': date_range('2013-01-01 09:00:00', periods=3),
                         'B': np.arange(3.0)})