rewrite logic of fetching solr cores in Acquia Search

This has been committed to the 3.2.x branch.

There are two logic changes between 3.1 and 3.2, which were expected but not implemented right:

1) Read Only is supposed to be TRUE in all local cases unless explicitly overridden
2) Config settings for acquia search get overwritten by configuration in Settings.php. If you previously used config AND settings, you must use only Settings. This will be added to the search documentation as we go through the Search 3.2 beta phase.

Automatically closed - issue fixed for 2 weeks with no activity.

@japerry - when we install site with acquia_search 3.2.x-dev we are getting below error and solr core is not getting attached. Kindly have a look at the screenshot below.

Forgot to add another error when we install site or run drush updb