Add aliases for StringIO.StringIO

cStringIO doesn't handle unicode, StringIO does. With py2/py3
compatable code we can easily find ourselves getting passed
unicode so we don't alias cStringIO

Signed-off-by: Noel Power <noel.power@suse.com>
Reviewed-by: Alexander Bokovoy <ab@samba.org>

python/samba/compat.py

@@ -30,6 +30,10 @@ if PY3:
     integer_types = int,
     string_types = str
     text_type = str
+
+    # alias
+    import io
+    StringIO = io.StringIO
 else:
     # compat functions
     from urllib import quote as urllib_quote
@@ -39,3 +43,7 @@ else:
     integer_types = (int, long)
     string_types = basestring
     text_type = unicode
+
+    # alias
+    import StringIO
+    StringIO = StringIO.StringIO