False negative result when SMB signing enabled

[mpgn]

When SMB signing is enabled, the test doesn't work properly. I have a Windows server vulnerable to CVE-2019-1040 but the scanner says it's not. But if I disabled smb signing (Not required), the magic happens, the server is now vulnerable.

Example when SMB signing is enabled (Required):

Example when SMB signing is disabled (Not required), same target is now vulnerable

[Dliv3]

Hi, I think I have fixed this issue, and it works in my environment, plz check it. If it works in your environment too, i will make a PR