chanegd permissions after re-creating a char device under /dev

A
```
--dev-bind /dev/steve /dev/steve
```
gives for an existing device _/dev/steve_ the right permissions within an image:
```
crw-rw---- 1 steve jobserver 247, 0 Dec 20 09:34 /dev/steve
```
But if the jobserver at the host is restarted, then the device will be recreated there. The udev rules
```
# cat /etc/udev/rules.d/99-steve.rules
ACTION=="add", ENV{DEVNAME}=="/dev/steve", OWNER="steve", GROUP="jobserver", MODE="660"
```
ensures right perms after restart at the host. But for bubblewraped images the permissions within the image are set to user _root_ now.