Add info about the waiting time

Author: wchen-r7

modules/exploits/windows/smb/group_policy_startup.rb

@@ -19,7 +19,8 @@ def initialize(info={})
         a SMB shared resource that will provide a payload through a VBS file. Startup scripts
         will be executed with SYSTEM privileges, while logon scripts will be executed with the
         user privileges. Have into account which the attacker still needs to redirect the
-        target traffic to the fake SMB share to exploit it successfully.
+        target traffic to the fake SMB share to exploit it successfully. Please note in some
+        cases, it will take 5 to 10 minutes to receive a session.
       },
       'Author'      =>
         [