[python] can't find shared lib

[Patrick Totzke]

Hi everyone,
It seems we have a problem with ctypes and libnotmuch:
I manually removed everything notmuch related from my system and pulled the latest master branch from git.
After a successful make;sudo make install;
i installed the python bindings from notmuch/bindings/python
via `sudo python ./setup.py install`, which also succeeded. However, If I start using the bindings I get:

```...
  File "/usr/local/lib/python2.7/dist-packages/notmuch/__init__.py", line 55, in <module>
    from notmuch.database import Database, Query
  File "/usr/local/lib/python2.7/dist-packages/notmuch/database.py", line 22, in <module>
    from notmuch.globals import nmlib, STATUS, NotmuchError, Enum, _str
  File "/usr/local/lib/python2.7/dist-packages/notmuch/globals.py", line 28, in <module>
    raise ImportError("Could not find shared 'notmuch' library.")
ImportError: Could not find shared 'notmuch' library.
```

Any ideas?
best,
/p