Use vprint for check because of rules

Author: wchen-r7

modules/exploits/multi/http/struts2_content_type_ognl.rb

@@ -75,7 +75,7 @@ def check
     end
 
     if resp && resp.code == 200 && resp.headers[var_a]
-      print_good("Victim operating system: #{resp.headers[var_a]}")
+      vprint_good("Victim operating system: #{resp.headers[var_a]}")
       Exploit::CheckCode::Vulnerable
     else
       Exploit::CheckCode::Safe