Fix python meterpreter subprocess deadlock and file descriptor leak

[adfoster-r7]

Fix python meterpreter subprocess deadlock and file descriptor leak caused by the stdout/stderr file descriptors not being closed

rapid7/metasploit-payloads#653

Verification

• Verify the commands work as expected and there isn't a file descriptor leak present in this scenario - Fix python meterpreter subprocess deadlock and file descriptor leak metasploit-payloads#653

[cgranleese-r7]

Before

After

route

meterpreter > route

IPv4 network routes
===================

    Subnet           Netmask          Gateway        Metric  Interface
    ------           -------          -------        ------  ---------
    0.0.0.0          0.0.0.0          192.168.1.254  0       en0

ipconfig

meterpreter > ipconfig

Interface  0
============
Name         : lo0

[cgranleese-r7]

Release Notes

This PR fixes Python Meterpreter subprocess deadlock and file descriptor leak caused by the stdout/stderr file descriptors not being closed.