Updated mssclient.py to Python3.

[0xdf-0xdf]

With python2 largely going away, and things like pip2 and python setup tools are difficult to find and install. Even just getting impacket as Python2 onto a new VM is challenging.

Updated to Python3 required small changes.

• byte strings where needed
• import _thread instread of thread
• replaced encode.('hex') with hex()

Also moved listening message to where listening
actually happens. On slow machines, can give the
impression that it is listening before it is.

Changes to be committed:
modified: mssqlclient.py

[xassiz]

Hey! We've thought about a Python3 release but keeping Python2 compatibility as well, like other Impacket examples do.

We are open for a new pull request if you want to. Thank you!

[ToBeatElite]

The upload and download features you've came up with are awesome, and 0xdf has already ported it to python3. I feel like putting that code to the main impacket mssqlclient.py could be epic so it's there by default for everyone. is there some objection against doing this bc this repo is years old and it should not be too hard to integrate it into the impacket repo? i dont intent to sound like "Why don't u push your code to the main repo", im just genuinely curious since im sure these functions would be helpful