add CheckCode:Safe

Author: Chocapikk

modules/exploits/multi/http/spip_porte_plume_previsu_rce.rb

@@ -86,6 +86,8 @@ def check
     elsif rversion < Rex::Version.new('4.1.0')
       return Exploit::CheckCode::Appears("The detected SPIP version (#{rversion}) is vulnerable.")
     end
+
+    return Exploit::CheckCode::Safe("The detected SPIP version (#{rversion}) is not vulnerable.")
   end
 
   def php_exec_cmd(encoded_payload)