Travis complaint: access to headers['set-cookie']

Assuming that res.get_cookies is analagous, quick scan of the
method indicates it generates a similar string to the original
content in the headers.

modules/auxiliary/server/http_proxy.rb

@@ -96,8 +96,8 @@ def log_response(cli,res)
       info[:ctype] = res.headers['content-type']
     end
 
-    if res.headers['set-cookie']
-      info[:cookie] = res.headers['set-cookie']
+    if res.get_cookies and not res.get_cookies.empty?
+      info[:cookie] = res.get_cookies
     end
 
     if res.headers['authorization']