Fix "TypeError: an integer is required" when specifying local_ini

I get this error when specfying `local_ini`:

```
You have installed Apache CouchDB, time to relax.
couchdb: cmmi failed: /var/folders/xd/33hpppf16yj0khx4fvq8qw2c0000gn/T/tmpCM51v6buildout-couchdb
While:
  Installing couchdb.

An internal error occurred due to a bug in either zc.buildout or in a
recipe being used:
Traceback (most recent call last):
  File "/Users/filip/.buildout/eggs/zc.buildout-1.5.2-py2.7.egg/zc/buildout/buildout.py", line 1805, in main
    getattr(buildout, command)(args)
  File "/Users/filip/.buildout/eggs/zc.buildout-1.5.2-py2.7.egg/zc/buildout/buildout.py", line 584, in install
    installed_files = self[part]._call(recipe.install)
  File "/Users/filip/.buildout/eggs/zc.buildout-1.5.2-py2.7.egg/zc/buildout/buildout.py", line 1297, in _call
    return f()
  File "/Users/filip/.buildout/eggs/zc.recipe.cmmi-1.3.4-py2.7.egg/zc/recipe/cmmi/__init__.py", line 99, in install
    self.build()
  File "/Users/filip/.buildout/eggs/zc.recipe.cmmi-1.3.4-py2.7.egg/zc/recipe/cmmi/__init__.py", line 182, in build
    self.cmmi(dest)
  File "/Users/filip/.buildout/eggs/buildout_couchdb-0.1-py2.7.egg/buildout_couchdb/__init__.py", line 80, in cmmi
    ft.write(f.read(self.inifile))
TypeError: an integer is required
```

Fix attached.