build_solr_schema field type conflict

Hi, I have some indexes with same field for different models and different types

Example:

class CompanyIndex(indexes.SearchIndex, indexes.Indexable):
        country = indexes.IntegerField(null=True)

class OrgIndex(indexes.SearchIndex, indexes.Indexable):
    country = indexes.MultiValueField(null=True)

the result of build schema will be:
< field name="country" type="text_en" indexed="true" stored="true" multiValued="true" / >

one field with multivalue field set to True ...

and as a result I get an exception

Traceback (most recent call last):
  File "<console>", line 1, in <module>
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/query.py", line 266, in __getitem__
    self._fill_cache(start, bound)
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/query.py", line 166, in _fill_cache
    results = self.query.get_results(**kwargs)
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/backends/__init__.py", line 644, in get_results
    self.run(**kwargs)
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/backends/solr_backend.py", line 697, in run
    results = self.backend.search(final_query, **search_kwargs)
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/backends/__init__.py", line 34, in wrapper
    return func(obj, query_string, *args, **kwargs)
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/backends/solr_backend.py", line 133, in search
    return self._process_results(raw_results, highlight=kwargs.get('highlight'), result_class=kwargs.get('result_class', SearchResult), distance_point=kwargs.get('distance_point'))
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/backends/solr_backend.py", line 382, in _process_results
    additional_fields[string_key] = index.fields[string_key].convert(value)
  File "/usr/local/bin/tpp/lib/python3.3/site-packages/haystack/fields.py", line 232, in convert
    return int(value)
TypeError: int() argument must be a string or a number, not 'list'

Start by tracing schema generation for build_solr_schema, then inspect haystack/backends/solr_backend.py and haystack/fields.py where the traceback reaches result conversion. Check existing tests around schema fields and Solr result processing; done means indexes sharing a field name with different types no longer produce an incompatible schema or a list-to-integer conversion failure.