Remove control 'os-08' because entropy is always at 256

[andrejmaya]

Is your feature request related to a problem? Please describe.
inspec is failing at the control 'os-08' step on most of the newer kernels. This happened because of changes in newer Linux versions to RNG’s crypto and backports to older LTS Kernels. Basically, the entropy_avail number is now meaningless.

Describe the solution you'd like
Remove the control check os-08 here: https://github.com/dev-sec/linux-baseline/blob/master/controls/os_spec.rb#L230

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
see here:
https://askubuntu.com/questions/1427470/entropy-is-stuck-at-256-after-upgrading-to-kernel-5-15-0-47

[rndmh3ro]

Sounds reasonable to me!