Remove workaround in Sync supervised users test

Remove workaround in Sync supervised users test

Now that crbug.com/422508 is fixed, we can remove the call that made the
test work.

BUG=422508
Committed: https://crrev.com/82d056a6c81cffbbbe216ece04105227cd38fd99
Cr-Commit-Position: refs/heads/master@{#300026}

[pval...(no longer on Chromium), 2014-10-16 21:19:09]

pvalenzuela@chromium.org changed reviewers:
+ zea@chromium.org

[Nicolas Zea, 2014-10-16 21:20:28]

lgtm

[pval...(no longer on Chromium), 2014-10-16 21:26:31]

The CQ bit was checked by pvalenzuela@chromium.org

[commit-bot: I haz the power, 2014-10-16 21:27:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/657283003/1

[commit-bot: I haz the power, 2014-10-16 23:30:30]

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

[commit-bot: I haz the power, 2014-10-16 23:30:31]

Exceeded time limit waiting for builds to trigger.

[pval...(no longer on Chromium), 2014-10-17 00:30:29]

The CQ bit was checked by pvalenzuela@chromium.org

[commit-bot: I haz the power, 2014-10-17 00:31:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/657283003/1

[commit-bot: I haz the power, 2014-10-17 00:33:23]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-17 00:34:16]

Patchset 1 (id:??) landed as
https://crrev.com/82d056a6c81cffbbbe216ece04105227cd38fd99
Cr-Commit-Position: refs/heads/master@{#300026}