IPython.utils.process.getoutput returns stderr

[juliantaylor]

the doc of IPython.utils.process.getoutput says is returns stdout, but it returns stderr too.
To reproduce fix the broken testcase due to multiple definition:

--- a/IPython/utils/tests/test_process.py
+++ b/IPython/utils/tests/test_process.py
@@ -125,7 +125,7 @@ def test_getoutput_quoted2(self):
         out = getoutput("python -c 'print (\"1\")'")
         self.assertEqual(out.strip(), '1')

-    def test_getoutput(self):
+    def test_getoutput_error(self):

and get:

FAIL: test_getoutput

self.assertEqual(out, 'on stdout')
AssertionError: 'on stdouton stderr' != 'on stdout'
- on stdouton stderr
+ on stdout