Automatic merge from submit-queue (batch tested with PRs 46678, 45545, 47375)

bazel: update debian-iptables-amd64 digest

**What this PR does / why we need it**: upstream debian has fixed several CVEs recently, so we should apply those fixes:
* CVE-2017-2616
* CVE-2017-6512

x-ref #47386

**Special notes for your reviewer**: nothing has been pushed yet, so this will likely fail many of the tests.

Do you think these version numbers make sense? We also need to fix debian-iptables v5, and I don't know what to do there. (v5.1?)

**Release note**:

```release-note
NONE
```
/assign @timstclair