Fix build_deb.sh script to work for any out directory, not only out/Release

Fix build_deb.sh script to work for any output directory.

Previously build_deb.sh was assuming that the build is in out/Release,
which is not always correct, particularly with GN.

BUG=512899
Committed: https://crrev.com/030286fd630303f825c46509ab85c2cb78067c11
Cr-Commit-Position: refs/heads/master@{#357658}

[Sergey Ulanov, 2015-11-03 19:59:16]

Description was changed from

==========
Fix build_deb.sh script to work for any out directory, not only out/Release

BUG=512899
==========

to

==========
Fix build_deb.sh script to work for any output directory.

Previously build_deb.sh was assuming that the build is in out/Release,
which is not always correct, particularly with GN.

BUG=512899
==========

[Sergey Ulanov, 2015-11-03 19:59:21]

sergeyu@chromium.org changed reviewers:
+ dpranke@chromium.org, lambroslambrou@chromium.org

[Dirk Pranke, 2015-11-03 21:12:12]

lgtm

[Lambros, 2015-11-03 21:20:34]

lgtm

[Sergey Ulanov, 2015-11-03 21:55:15]

The CQ bit was checked by sergeyu@chromium.org

[commit-bot: I haz the power, 2015-11-03 21:57:02]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1412653005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1412653005/1

[commit-bot: I haz the power, 2015-11-03 22:40:52]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-11-03 22:42:14]

Patchset 1 (id:??) landed as
https://crrev.com/030286fd630303f825c46509ab85c2cb78067c11
Cr-Commit-Position: refs/heads/master@{#357658}