go test hangs

[maruel]

I wanted to contribute a change but I couldn't run unit tests...

On go 1.10.1 (built myself)

go get github.com/StackExchange/wmi
go test github.com/StackExchange/wmi

@cdffdb33acae0e14efff

Expected:
Tests pass quickly.

Actual:
Tests hang.

Running with -v prints out error about exception in GetMemoryUsage.