Always write .landmines

Always write .landmines

Otherwise, if .landmines exists, and isn't clobbered by the clobber in
compile.py, every build will cause a clobber until .landmines is removed.

Trying to fix http://crbug.com/375459 brought this up. In that case
compile.py wasn't removing .landmines, which is necessary in the case
of a landmines change on two subsequent builds. If .landmines isn't
maintained, then there's nothing to diff against on the second build
and so a clobber won't be correctly triggered.

R=iannucci@chromium.org,kbr@chromium.org
BUG=376359
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=272341

[Ken Russell (switch to Gerrit), 2014-05-22 18:19:17]

LGTM. I think this, combined with the change to compile.py to skip deleting
.landmines during clobber builds, will fix both Issue 375459 and Issue 376359.

[scottmg, 2014-05-22 18:21:59]

The CQ bit was checked by scottmg@chromium.org

[scottmg, 2014-05-22 18:23:14]

On 2014/05/22 18:19:17, Ken Russell wrote:
> LGTM. I think this, combined with the change to compile.py to skip deleting
> .landmines during clobber builds, will fix both Issue 375459 and Issue 376359.

Thanks. I'll CQ this now and wait a day or two before relanding the other so
that all the bots get past this revision before getting compile.py.

Sorry for the hassle with this and thanks for help diagnosing.

[commit-bot: I haz the power, 2014-05-22 18:24:41]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/scottmg@chromium.org/293983017/1

[commit-bot: I haz the power, 2014-05-22 22:12:53]

Change committed as 272341