Properly close some leaked resources.

IPython/utils/openpy.py

@@ -32,7 +32,7 b" def source_to_unicode(txt, errors='replace', skip_encoding_cookie=True):"
     except SyntaxError:
         encoding = "ascii"
     buffer.seek(0)
-    text = TextIOWrapper(buffer, encoding, errors=errors, line_buffering=True)
+    with TextIOWrapper(buffer, encoding, errors=errors, line_buffering=True) as text:
     text.mode = 'r'
     if skip_encoding_cookie:
         return u"".join(strip_encoding_cookie(text))