[Bug?] Invalid queries are not filling the err variable

Hi there,

I happened to notice that an invalid queries like:

• SELECT * FROM ThisDoesNotExist (invalid class)
• SELECT ThisDoesNotExist FROM Win32_OperatingSystem (invalid Property)

Which are correctly failing with an error in WmiExplorer:

And are producing EventViewer's Errors 5858 in the Microsoft > Windows > WMI Activity > Operational are silently ignored.

Example:

package cim

import (
	"log"
	"testing"

	"github.com/stretchr/testify/assert"
)

func Test_ClassDoesNotExist(t *testing.T) {
	sm := NewWmiSessionManager()
	defer sm.Close()
	defer sm.Dispose()
	session, err := sm.GetLocalSession("root\\cimv2")
	if err != nil {
		log.Printf("Could not get session %v", err)
		return
	}
	_, err = session.Connect()
	if err != nil {
		log.Printf("Could not connect session %v", err)
		return
	}
	defer session.Close()
	defer session.Dispose()

	query := "SELECT * FROM ThisDoesNotExist"
	_, err = session.QueryInstances(query)

	assert.Error(t, err)

	query = "SELECT DoesNotExist FROM Win32_OperatingSystem"
	_, err = session.QueryInstances(query)

	assert.Error(t, err)

}

The expected behavior is that such failures should fill the err variable to let programmers deal with invalid queries.

Start with the provided Test_ClassDoesNotExist reproducer and trace session.QueryInstances for how invalid WMI queries are handled. Run the test with both invalid queries; done means each failure populates err so callers can detect it.