Debian Support

When there are importers with an empty "config" dict, migration 0004 will throw a KeyError

Applying migration pulp_deb.plugins.migrations.0004_add_distribution failed.

Halting migrations due to a migration failure.
'releases'
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/pulp/server/db/manage.py", line 279, in main
    return _auto_manage_db(options)
  File "/usr/lib/python2.7/site-packages/pulp/server/db/manage.py", line 346, in _auto_manage_db
    migrate_database(options)
  File "/usr/lib/python2.7/site-packages/pulp/server/db/manage.py", line 175, in migrate_database
    update_current_version=not options.test)
  File "/usr/lib/python2.7/site-packages/pulp/server/db/migrate/models.py", line 206, in apply_migration
    migration.migrate()
  File "/usr/lib/python2.7/site-packages/pulp_deb/plugins/migrations/0004_add_distribution.py", line 74, in migrate
    distributions = repo_importer['config']['releases'].split(',')
KeyError: 'releases'