The infamous `NetlinkError: (17, 'File exists')` started to bug us again
due to changes in when cri-o is deleting network namespaces. This patch
is an ultimate brute-force attempt to fix the problem. The idea is that
on NetlinkError kuryr-daemon will iterate over *all* network namespaces
in the system and delete interfaces that have the conflicting VLAN ID.
Closes-Bug: 1892388
Change-Id: I6672ed0e0db99a91b68cc4d9e74a33d8a9bcf0ca