buffet: only get ipv4 address from a host/service

Jetstream devices don't have ipv6 supprot yet.

BUG=b:34200387
TEST=manual groobe test

Change-Id: Ifc38d2d04f5d81ff1eafc0c1b459adf3f6245902
Reviewed-on: https://chromium-review.googlesource.com/447460
Reviewed-by: Julan Hsu <julanhsu@google.com>
Commit-Queue: Julan Hsu <julanhsu@google.com>
Tested-by: Julan Hsu <julanhsu@google.com>
1 file changed