Convert to JSON only if the response is not nil

Signed-off-by: Aravinda VK <[email protected]>

lib/kadalu/binnacle/plugins/http.rb

@@ -129,7 +129,7 @@ def self.output_from_response(response)
       case response_type
       when 'json'
         begin
-          outdata[:json] = JSON.parse(response.body)
+          outdata[:json] = JSON.parse(response.body) if response.body.is_a?(String)
         rescue JSON::ParserError
           outdata[:json] = nil
         end