swig-py3 str/bytes difference in svn_config_*()

[Daniel Shahaf]

With swig-py3 in trunk:

>>> from svn.core import *
>>> svn_config_get_user_config_path(None, '')
b'/home/daniel/.subversion'
>>> d = _
>>> svn_config_ensure(d)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "${prefix}/lib/svn-python/libsvn/core.py", line 6014, in 
svn_config_ensure
    return _core.svn_config_ensure(*args)
TypeError: svn_config_ensure() argument 1 must be str or None, not bytes
>>> svn_config_ensure(d.decode())                                               
>>>                          
>>> 

svn_config_get_user_config_path() returns bytes but svn_config_ensure() expects
str.  I expected them both to use the same type, since in C they do:
svn_config_get_user_config_path() has a «const char **» output parameter and
svn_config_ensure() has a «const char *» input parameter.

Cheers,

Daniel

P.S. Unrelated issue: «svn_config_get_user_config_path(None, None)» raises
TypeError, even though at the C level the second input parameter, FNAME,
is allowed to be NULL.