Update .exe and .dmg file error messages.

Update .exe and .dmg file error messages.

Modify error message because previous message is less information.

BUG=399333
TEST=manually

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=288923

[iseki, 2014-08-11 04:41:14]

Please review it.

[hirono, 2014-08-11 04:57:48]

lgtm!

[iseki, 2014-08-11 05:07:43]

The CQ bit was checked by iseki@chromium.org

[commit-bot: I haz the power, 2014-08-11 05:08:47]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/iseki@chromium.org/455273002/1

[commit-bot: I haz the power, 2014-08-11 06:21:36]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[commit-bot: I haz the power, 2014-08-11 06:24:44]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2014-08-11 06:24:45]

Try jobs failed on following builders:
  chromium_presubmit on tryserver.chromium.linux
(http://build.chromium.org/p/tryserver.chromium.linux/builders/chromium_presub...)

[iseki, 2014-08-11 06:37:19]

Please review it.

[yoshiki, 2014-08-12 05:02:09]

Sorry, I missed this. LGTM

[iseki, 2014-08-12 05:05:32]

On 2014/08/12 05:02:09, yoshiki wrote:
> Sorry, I missed this. LGTM

Thank you for your review.

[iseki, 2014-08-12 05:05:41]

The CQ bit was checked by iseki@chromium.org

[commit-bot: I haz the power, 2014-08-12 05:07:21]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/iseki@chromium.org/455273002/1

[commit-bot: I haz the power, 2014-08-12 05:50:11]

Change committed as 288923