tree 3001b2fff4d582cfb273827f7c7215e2a8774f7a
parent cf1f2a033089cf8354e2fd6d871852adf001b97c
author Bert Muthalaly <stijlist@google.com> 1544664462 -0500
committer CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org> 1544733937 +0000

[netstack] Add a fallback name for network bridges

...in case one hasn't been configured. We can keep this code path the
same even if/when netcfg eventually ends up naming bridges, because
we'll want the affordance of seeing `brN` in ifconfig output if naming
fails in other ways.

Tested:
- sudo tunctl -u stijlist -t qemu-extra
- sudo ifconfig qemu-extra up
- fx run -kN -- -netdev type=tap,ifname=qemu-extra,script=no,downscript=no,id=net1 -device e1000,netdev=net1,mac=52:54:00:63:5e:7b
- fx shell "ifconfig bridge ethp0003 ethp0004"
- fx shell "ifconfig" | grep br4

Change-Id: Ief6f9db67720d90ca7294e0117073b5281b32bf3