Specify "dont use acquia http transport" in options / search_api_acquia_overrides

On a development setup I wan't to point Drupal to use my localhost Solr instead of Acquia Search (without defining another server because my servers are handled via features).

I can point to my localhost Solr by adding host, port and path to 'search_api_acquia_overrides' in my settings file, but I can't connect to it using SearchApiAcquiaSearchHttpTransport.

The attached patch introduces an option named 'dont_use_acquia_http_transport' which will leave SearchApiSolrHttpTransport as transport object.

Now I can put the following into my settings.php on my development environment and have search running against the local Solr server:

$conf['search_api_acquia_overrides'] = array(
  'acquia_search' => array(
    'host' => 'localhost',
    'port' => '8983',
    'dont_use_acquia_http_transport' => TRUE,
  ),
);