parallels: simplify regex for vm files

The original regex had multiple occurrences of a `.+?' pattern, which is
essentially the same as a `.*', so we replace the former by the latter
for clarity.

Additionally, since the beginning of the path does not interest us, we
can ignore it from the regex, and only start matching once we have found
what's interesting for us, further simplifying the expression.

post-processor/vagrant/parallels.go

@@ -43,11 +43,11 @@ func (p *ParallelsProvider) Process(ui packersdk.Ui, artifact packersdk.Artifact
 		}
 
 		tmpPath := filepath.ToSlash(path)
-		pathRe := regexp.MustCompile(`^(.+?)([^/]+\.(pvm|macvm)/.+?)$`)
-		matches := pathRe.FindStringSubmatch(tmpPath)
+		pathRe := regexp.MustCompile(`[^/]+\.(pvm|macvm)/.+$`)
+		match := pathRe.FindString(tmpPath)
 		var pvmPath string
-		if matches != nil {
-			pvmPath = filepath.FromSlash(matches[2])
+		if match != "" {
+			pvmPath = filepath.FromSlash(match)
 		} else {
 			continue // Just copy a pvm
 		}