network: print Ethernet Link-Layer DHCP client ID with leading 0's
This is a small cosmetic change.
Before:
Offered DHCP leases: 192.168.0.183 (to 0:9:a7:36:bc:89)
After:
Offered DHCP leases: 192.168.0.183 (to 00:09:a7:36:bc:89)
(cherry picked from commit 8e664ab6)
(cherry picked from commit 133354a3)