Reland of Fix typo in install-sysroot.py

Reland of Fix typo in install-sysroot.py (patchset #1 id:1 of https://codereview.chromium.org/1315773003/ )

Reason for revert:
The check_licenses script has been fixed, and it cycled green:
https://build.chromium.org/p/chromium/builders/Linux/builds/66708

Original issue's description:
> Revert of Fix typo in install-sysroot.py (patchset #2 id:20001 of https://codereview.chromium.org/1317973005/ )
>
> Reason for revert:
> Caused check_licenses to fail:
>
> https://build.chromium.org/p/chromium/builders/Linux/builds/66701
>
> Original issue's description:
> > Fix typo in install-sysroot.py
> >
> > install-sysroot.py was intended to default to installing
> > the sysroot ia32, but within this script 'i386' is used to
> > refer to this architecture.
> >
> > This most likely went unnoticed since the ia32 builder
> > either use branding=Official, or explicitly set
> > use_sysroot=1, or have a complete set of packages for
> > cross building on the host system.
> >
> > BUG=504446
> >
> > Committed: https://crrev.com/1d62049b4c176fbd43bed90fc9a76273b11ad406
> > Cr-Commit-Position: refs/heads/master@{#347821}
>
> TBR=dpranke@chromium.org,sbc@chromium.org
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
> BUG=504446
>
> Committed: https://crrev.com/3b27a2de111759359162bcad49753e17ee1cf002
> Cr-Commit-Position: refs/heads/master@{#347839}

TBR=dpranke@chromium.org,sbc@chromium.org,chrishtr@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=504446
Committed: https://crrev.com/064aca24669857d48458749952a3bc7c9c516e63
Cr-Commit-Position: refs/heads/master@{#347901}

[Adrian Kuegel, 2015-09-09 10:27:38]

Created Reland of Fix typo in install-sysroot.py

[commit-bot: I haz the power, 2015-09-09 10:27:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1324853005/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1324853005/1

[commit-bot: I haz the power, 2015-09-09 10:28:19]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-09 10:29:24]

Patchset 1 (id:??) landed as
https://crrev.com/064aca24669857d48458749952a3bc7c9c516e63
Cr-Commit-Position: refs/heads/master@{#347901}

[Sam Clegg, 2015-09-09 12:55:26]

On 2015/09/09 10:29:24, commit-bot: I haz the power wrote:
> Patchset 1 (id:??) landed as
> https://crrev.com/064aca24669857d48458749952a3bc7c9c516e63
> Cr-Commit-Position: refs/heads/master@{#347901}

Thanks!  lgtm