Reverse numpy compat changes to tslib.pyx

Title is self-explanatory.  xref #13148.

Author: gfyoung <[email protected]>

Closes #13246 from gfyoung/tslib-compat-undo and squashes the following commits:

66160f9 [gfyoung] Reverse numpy compat changes to tslib.pyx

Author: gfyoung

doc/source/whatsnew/v0.18.2.txt

@@ -54,7 +54,6 @@ API changes
 
 
 - Non-convertible dates in an excel date column will be returned without conversion and the column will be ``object`` dtype, rather than raising an exception  (:issue:`10001`)
-- Compat with ``np.round`` and timestamps (:issue:`12811`)
 - An ``UnsupportedFunctionCall`` error is now raised if numpy ufuncs like ``np.mean`` are called on groupby or resample objects (:issue:`12811`)
 
 .. _whatsnew_0182.api.tolist:

pandas/tseries/tests/test_tslib.py

@@ -1337,14 +1337,11 @@ def test_shift_months(self):
                 tm.assert_index_equal(actual, expected)
 
     def test_round(self):
-        # see gh-12811
         stamp = Timestamp('2000-01-05 05:09:15.13')
 
         def _check_round(freq, expected):
             result = stamp.round(freq=freq)
-            npResult = np.round(stamp, freq)
             self.assertEqual(result, expected)
-            self.assertEqual(npResult, expected)
 
         for freq, expected in [
             ('D', Timestamp('2000-01-05 00:00:00')),
@@ -1353,16 +1350,9 @@ def _check_round(freq, expected):
         ]:
             _check_round(freq, expected)
 
-        msg = "the 'out' parameter is not supported"
-        tm.assertRaisesRegexp(ValueError, msg, np.round,
-                              stamp, 'D', out=[])
-
-        # 'freq' is a required parameter, so we cannot
-        # assign a default should the user accidentally
-        # assign a 'decimals' input instead
         msg = "Could not evaluate"
-        tm.assertRaisesRegexp(ValueError, msg, np.round,
-                              stamp, 2)
+        tm.assertRaisesRegexp(ValueError, msg,
+                              stamp.round, 'foo')
 
 
 class TestTimestampOps(tm.TestCase):

pandas/tslib.pyx

@@ -387,7 +387,7 @@ class Timestamp(_Timestamp):
             result = result.tz_localize(self.tz)
         return result
 
-    def round(self, freq, *args, **kwargs):
+    def round(self, freq):
         """
         Round the Timestamp to the specified resolution
 
@@ -403,8 +403,6 @@ class Timestamp(_Timestamp):
         ------
         ValueError if the freq cannot be converted
         """
-        from pandas.compat.numpy.function import validate_round
-        validate_round(args, kwargs)
         return self._round(freq, np.round)
 
     def floor(self, freq):