[Windows] Ignore disk I/O counters for drives that are not accessible

[mx-psi]

Summary

• OS: Windows
• Bug fix: yes (debatable?)
• Type: core
• Fixes: #1974

Description

Ignore permission errors on Windows when fetching I/O counters. I would classify this as a bug fix since this error only happens because of the way the function works (by exhaustively checking every possible drive), and nothing in the function description indicates it should work like this.

Nonetheless I understand it is debatable (see proposed alternative on linked issue if this is not an acceptable patch).

[mx-psi]

@giampaolo Would it be possible for you to have a look at this?

Also, I wonder if I can have a timeline on when this or my previous PR #1961 will be in a released version of psutil. It would be awesome to be able to share a rough date with customers of my employer who need these fixes.

Thanks in advance :)

[mx-psi]

@giampaolo friendly ping, could you have a look?