Handle pg search ordering bug for cookbooks search

There appears to be an issue with the pg search gem
https://github.com/Casecommons/pg_search/issues/129 that breaks ordering
after a search has been performed. This changes the controller flow so
ordering is done before searching and also adds a spec originally used
to reproduce the bug but seems handy to keep around in case pg search
misbehaves again.
Merge pull request #347 from opscode/search-ordering

Handle pg search ordering bug for cookbooks search