Land rapid7#5168, more fail_with fixes

Author: wvu

modules/exploits/unix/webapp/wp_nmediawebsite_file_upload.rb

@@ -63,15 +63,15 @@ def exploit
         begin
           new_php_pagename = JSON.parse(res.body)["filename"]
         rescue JSON::ParserError
-          new_php_pagename = ''
+          fail_with(Failure::Unknown, 'Unable to parse JSON data for the filename')
         end
         print_good("#{peer} - Our payload is at: #{new_php_pagename}. Calling payload...")
         register_files_for_cleanup(new_php_pagename)
       else
         fail_with("#{peer} - Unable to deploy payload, server returned #{res.code}")
       end
     else
-      fail_with('ERROR')
+      fail_with(Failure::Unknown,'ERROR')
     end
 
     print_status("#{peer} - Calling payload...")