Merge pull request #8677 from jubianchi/api-500-json

Send 500 errors as JSON in the API

lib/api/api.rb

@@ -19,7 +19,7 @@ module API
       message << "  " << trace.join("\n  ")
 
       API.logger.add Logger::FATAL, message
-      rack_response({ 'message' => '500 Internal Server Error' }, 500)
+      rack_response({ 'message' => '500 Internal Server Error' }.to_json, 500)
     end
 
     format :json