Fix get nvt

[y0urself]

What:

Fixing get_nvt().

Why:

There is a gvmd-related error, that get_nvt with the timeout parameter can't be used.

>>> nvts2 = gmp.get_nvt(nvt_oid='1.3.6.1.4.1.25623.1.0.814313')
Traceback (most recent call last):
...
gvm.errors.GvmResponseError: Response Error 400. The timeout attribute requires the details and config_id attributes

How:

Just remove that parameter that has been set to always true.

Checklist:

• Tests
• CHANGELOG Entry
• Documentation