return ThinkingSphinx::Search in search (#4357)

page_terms.replace(pages) will replace the page_terms with pages just fine.
But it returns the pages Array instead of page_terms. So we explicitly need
to return page_terms
Merge pull request #114 from azul/bugfix/4357-fix-pagination-with-sphinx

return ThinkingSphinx::Search in search (#4357)