Fix android envsetup permission issue.

Fix android envsetup permission issue.

CQ automatically adds +x to any file which ends with .sh
Since envsetup.sh doesn't have a shabang line, this has
causes several tree closures.  Fix this by adding a shabang
and detecting when script is not being sourced.

TBR=yfriedman
Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=182968

[commit-bot: I haz the power, 2013-02-16 11:27:24]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ilevy@chromium.org/12282018/1

[commit-bot: I haz the power, 2013-02-16 11:29:09]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/ilevy@chromium.org/12282018/1

[Yaron, 2013-02-19 16:51:09]

lgtm

[Nico, 2013-02-25 20:14:25]

The webkit chromium/android builder has been failing ever since this made it
into chromium:

http://build.webkit.org/builders/Chromium%20Android%20Release/builds/34535/st...

ERROR: envsetup must be sourced.

(first failing run:
http://build.webkit.org/builders/Chromium%20Android%20Release/builds/34035 roll
chromium deps 182150:183105)

[Nico, 2013-02-25 20:14:37]

*made it into webkit

[Isaac (away), 2013-02-27 07:04:44]

I had some trouble reproducing (and initially suspected the way gyp_webkit
sources bash), but after some debugging I can reproduce with this:

/bin/bash -c '. build/android/envsetup.sh'

Note the '/bin/bash'.  It looks like I need to check ${BASH_SOURCE[0]}  against
$0  to look if the script is being sourced.  I was trying to avoid that since
it's bash specific, but the reality is our script doesn't work in other shells
anyway, so I think it's acceptable, especially with our long term goal of
getting rid of envsetup.  Running  update-webkit-chromium on vm5-m5, envsetup.sh
reports the following variables settings:

$_   bash
$0   bash
${BASH_SOURCE[0]}   /mnt/data/b/........../build/android/envsetup.sh

Hence throwing an error if $0 = BASH_SOURCE[0] won't break gyp_webkit again.

[Isaac (away), 2013-02-27 07:08:05]

* the way gyp_webkit sources envsetup.sh