Merge pull request #2 from stolowski/fix-subsystem-with-existingdevices

Thank you for your contribution, the implemetnation is valid and have no negative impact on the existing code, go merge ! Cheers 

Fixes #1

crawler/device.go

@@ -53,14 +53,14 @@ func ExistingDevices(queue chan Device, errors chan error, matcher netlink.Match
 					return err
 				}
 
-				if matcher == nil || matcher.EvaluateEnv(env) {
+				kObj := filepath.Dir(path)
 
-					kObj := filepath.Dir(path)
+				// Append to env subsystem if existing
+				if link, err := os.Readlink(kObj + "/subsystem"); err == nil {
+					env["SUBSYSTEM"] = filepath.Base(link)
+				}
 
-					// Append to env subsystem if existing
-					if link, err := os.Readlink(kObj + "/subsystem"); err == nil {
-						env["SUBSYSTEM"] = filepath.Base(link)
-					}
+				if matcher == nil || matcher.EvaluateEnv(env) {
 
 					queue <- Device{
 						KObj: kObj,