dlp: stop generation of apiv2
dlp: stop generation of apiv2

There is a breaking change coming to this api. Disabling api
generation until that change lands.

Updates: #1969
Change-Id: Id5b4cdcb9df2a57375f5383bd417959b32e36b04
Reviewed-on: https://code-review.googlesource.com/c/gocloud/+/55990
Reviewed-by: Tyler Bui-Palsulich <b41e4aa57d2ad7eb1b29835a1b483e209dcc3c0e@google.com>
Reviewed-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>

googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go