Get rid of a couple references to IDR_WARNING

Get rid of a couple references to IDR_WARNING

This changes the appearance of the chrome://extensions warning banner (for the better, IMO)
This makes no difference to inspect.css because the version restriction was removed in 794befa4c5 and the css rules were dead code

BUG=505953
Committed: https://crrev.com/87f6aaa3de7b4c37088421de09e68c3eb01a48d7
Cr-Commit-Position: refs/heads/master@{#342777}

[Evan Stade, 2015-08-11 01:42:35]

estade@chromium.org changed reviewers:
+ dbeam@chromium.org

[Dan Beam, 2015-08-11 01:45:40]

lgtm

[Evan Stade, 2015-08-11 01:45:53]

The CQ bit was checked by estade@chromium.org

[commit-bot: I haz the power, 2015-08-11 01:46:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1284643005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1284643005/1

[commit-bot: I haz the power, 2015-08-11 02:43:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-11 02:44:12]

Patchset 1 (id:??) landed as
https://crrev.com/87f6aaa3de7b4c37088421de09e68c3eb01a48d7
Cr-Commit-Position: refs/heads/master@{#342777}