Fix GetImgFingerprint for small files.

Fix GetImgFingerprint for small files.

%06x was incorrectly adding leading zeros for small files, the value
should just be %x.

BUG=

Committed: https://crrev.com/55e00b641ba4fcb347f9b8821531682843c59f27
Cr-Commit-Position: refs/heads/master@{#304430}

[csharp, 2014-11-17 16:13:00]

csharp@chromium.org changed reviewers:
+ chrisha@chromium.org

[csharp, 2014-11-17 16:13:00]

Fixing as discussed in the email thread.

According to the code search, this is the only place in Chromium where
'%08X%06x' is used.

[Sigurður Ásgeirsson, 2014-11-17 16:15:49]

siggi@chromium.org changed reviewers:
+ siggi@chromium.org

[Sigurður Ásgeirsson, 2014-11-17 16:15:49]

The CQ bit was checked by siggi@chromium.org

[Sigurður Ásgeirsson, 2014-11-17 16:15:50]

lgtm

[commit-bot: I haz the power, 2014-11-17 16:16:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/726313006/1

[commit-bot: I haz the power, 2014-11-17 17:05:32]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-11-17 17:06:13]

Patchset 1 (id:??) landed as
https://crrev.com/55e00b641ba4fcb347f9b8821531682843c59f27
Cr-Commit-Position: refs/heads/master@{#304430}

[brucedawson, 2014-11-17 18:23:12]

brucedawson@chromium.org changed reviewers:
+ brucedawson@chromium.org

[brucedawson, 2014-11-17 18:23:12]

It's already checked in, but,
lgtm

[chrisha, 2014-11-17 18:24:31]

Awesome, lgtm!

[brucedawson, 2014-12-12 00:32:27]

This fix didn't work because this is not actually the copy of img_fingerprint.py
which our official builds use. csharp@ found the right file and re-did the same
fix. I just verified that it works. Details and the final fix are here:

https://chromereviews.googleplex.com/130777013/