tcollector.py: fix bad variable name in default host tag detection.

Signed-off-by: Vasiliy Kiryanov <vasiliy.kiryanov@gmail.com>
Debian package: fix of fail of adduser/addgroup commands if the user already exists.

Signed-off-by: Vasiliy Kiryanov <vasiliy.kiryanov@gmail.com>
Fix a TypeError: 'tuple' object does not support item assignment