Syntax Error fix in apipie_404.html.erb

The app wasn't displaying the '/apipie' path due to a syntax error in one of the view.
Added the missing parentheses and fixed ":href = link_to(..)" to ":href => link_to(..).
Merge pull request #246 from richardsondx/patch-1

Syntax Error fix in apipie_404.html.erb