The win_perf_counters input does not close query handles

[danielnelson]

Bug report

Based on code inspection, the win_perf_counters input does not close its handle using PdhCloseQuery. This will likely cause the handles to become lost if the Telegraf reloads the plugin.

Relevant telegraf.conf:

N/A

System info:

N/A

Steps to reproduce:

May not currently be possible since I don't think you can trigger a reload of plugins in Windows.

Expected behavior:

win_perf_counters should call PdhCloseQuery for every handle opened with PdhOpenQuery.

Actual behavior:

PdhCloseQuery is never called

Additional info:

Has not been verified. Discovered in code review of #2800

[danielnelson]

@vlastahajek Can you take a look at this and let me know if we need to address?

[vlastahajek]

@danielnelson This is handled in #4189.
I created reusable struct representing query, which closes previous query, during each open. Even it may not seems perfect from OOD perspective, I did it so to create simple GO mock-able abstraction with the least possible amount of business logic.