Gitlab runner doesn't parse virtualbox snapshot names properly due to broken regex

Summary

Virtualbox (on windows at least) outputs the snapshot information in a different format than what the code expects, resulting in the report that the snapshot cannot be found

I think this may be related to #3273

Steps to reproduce

1. Create VM
2. Add snapshot
3. register vm with base_snapshot set to snapshot name
4. send a job to it, and see in the job output the warning that the snapshot is not found

Expected behavior

The snapshot to be used in the job

Relevant logs and/or screenshots

The go code for parsing the list of snapshots from vboxmanage:

func HasSnapshot(vmName string, snapshotName string) bool {
	output, err := VBoxManage("snapshot", vmName, "list", "--machinereadable")
	if err != nil {
		return false
	}
	snapshotRe := regexp.MustCompile(fmt.Sprintf(`(?m)^Snapshot(Name|UUID)[^=]*="%s"$`, regexp.QuoteMeta(snapshotName)))
	snapshot := snapshotRe.FindStringSubmatch(output)
	return snapshot != nil
}

and a sample list of snapshots from vboxmanage using the above command vboxmanage snapshot {vmname} list --machinereadble

SnapshotName="gitlabrunner"
SnapshotUUID="xxx"
SnapshotName-1="snap1"
SnapshotUUID-1="xxx"
CurrentSnapshotName="snap1"
CurrentSnapshotUUID="xxx"
CurrentSnapshotNode="SnapshotName-1"

I've never coded in go, but I'd guestimate there are missing round brackets for the name / uuid value missing, like so:

snapshotRe := regexp.MustCompile(fmt.Sprintf(`(?m)^Snapshot(Name|UUID)[^=]*="(%s)"$`, regexp.QuoteMeta(snapshotName)))

Looking at the get Current Snapshot code below:

([^"]*) is used instead of %s, which is what I'd personally prefer to see

snapshotRe := regexp.MustCompile(fmt.Sprintf(`(?m)^Snapshot(Name|UUID)[^=]*="([^"]+)"$`, regexp.QuoteMeta(snapshotName)))

Environment description

virtualbox executor, on windows host.

Used GitLab Runner version

The code above is pulled from https://gitlab.com/gitlab-org/gitlab-runner/blob/master/helpers/virtualbox/control.go

I'm using 10.7.1