don't use use locale.getpreferredencoding(False)

instead use default locale.getpreferredencoding() in text.getdefaultencoding,
which seems better behaved.

IPython/utils/text.py

@@ -51,7 +51,7 b' def getdefaultencoding():'
         try:
             # There are reports of getpreferredencoding raising errors
             # in some cases, which may well be fixed, but let's be conservative here.
-            enc = locale.getpreferredencoding(False)
+            enc = locale.getpreferredencoding()
         except Exception:
             pass
     return enc or sys.getdefaultencoding()