Log Message:
py-libxml2: remove patch-python_libxml__wrap.h - the cause of PR pkg/52690

$ python3.6
Python 3.6.3 (default, Oct 27 2017, 17:16:29)
[GCC 5.4.0] on netbsd8
Type "help", "copyright", "credits" or \ 
"license" for more information.
>>> import libxml2
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/pkg/lib/python3.6/site-packages/libxml2.py", line 1, in \ 
<module>
    import libxml2mod
ImportError: /usr/pkg/lib/python3.6/site-packages/libxml2mod.so: Undefined PLT \ 
symbol "PyCObject_Check" (symnum = 488)