Fix a bug that link_to_next_page behaves like link_to_previous_page

This fixes #530
Do not use prev_page/next_page's options

it has extra keys like :current_page and :total_pages. Just pass the
original options so their behaviours don't change from version 0.15.1.

Also, {remote: false} doesn't have to be merged since options are passed
to link_to_next_page/link_to_previous_page directly.