Trigger a landmine on first-time landmine deployment.

Trigger a landmine on first-time landmine deployment.

Without this change, it is non-trivial to know during
runhooks, if a landmine was just triggered in a checkout
that doesn't have the initial landmines script CL yet, i.e.
that didn't create a .landmines file yet.

BUG=chromium:403263
LOG=n

Committed: https://crrev.com/0fff64da8b204dec3e5302b9ac3408664e8b19ee
Cr-Commit-Position: refs/heads/master@{#26842}

[Michael Achenbach, 2015-02-25 08:53:46]

machenbach@chromium.org changed reviewers:
+ jkummerow@chromium.org, jochen@chromium.org, tandrii@chromium.org

[Michael Achenbach, 2015-02-25 08:54:36]

PTAL

[jochen (gone - plz use gerrit), 2015-02-25 08:56:13]

lgtm

[Michael Achenbach, 2015-02-25 09:08:02]

The CQ bit was checked by machenbach@chromium.org

[commit-bot: I haz the power, 2015-02-25 09:09:33]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/954153002/1

[commit-bot: I haz the power, 2015-02-25 09:20:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-25 09:20:16]

Patchset 1 (id:??) landed as
https://crrev.com/0fff64da8b204dec3e5302b9ac3408664e8b19ee
Cr-Commit-Position: refs/heads/master@{#26842}