Merge lp://staging/~adeuring/charmworld/fixed-interfaces-mapping into lp://staging/~juju-jitsu/charmworld/trunk

use a static mapping for the charm index.

his branch removes the last remainig dynamic part of the mapping used
by the ElasticSearch index for charms.

The properties "requires" and "provides" of a charm are dictionaries
of the form

    {'relation_name': {'interface': 'http', ...}, ...}

which means that each relation name must appear as a property in the mapping.

The ES server gets charm data in the form

    {'_id': ...,
     'data': real_charm_data
     }

ElasticSearchClient._wrap_charm() now adds two entries "requires" and
"provides" that are lists of the relation data from charm["provides"]
and charm["requires"], respectively. The relation name is added to
the list entries.

This allows to define a static mapping for the relation data.

test_mapping_changes_during_indexing() requires an obvious change.
The test itself is now a bit flaky -- it might succeed accidentally:
As the comment for the old version notes, the result of the call of
get_mapping() does not necessarily incorporate possible mapping
changes after data has been added to the index. Hence it might make
sense to add a sleep(0.5) call to the test.

The change of the mapping and the related change of
ElasticSearchClient._get_text_query() require to reindex all charms.
This is done in an exodus.