Hook up "--threads" to gn help.

Hook up "--threads" to gn help.

This was documented but the flag was not hooked up to the help system so it didn't actually appear in "gn help switches".

Committed: https://crrev.com/62ce4f0ee6778343f52682294dc63784b02a7907
Cr-Commit-Position: refs/heads/master@{#349500}

[brettw, 2015-09-17 19:11:41]

brettw@chromium.org changed reviewers:
+ jam@chromium.org

[brettw, 2015-09-17 19:11:45]

The CQ bit was checked by brettw@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-09-17 19:12:26]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1357523003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1357523003/1

[commit-bot: I haz the power, 2015-09-17 19:28:40]

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

[commit-bot: I haz the power, 2015-09-17 19:28:41]

Dry run: This issue passed the CQ dry run.

[jam, 2015-09-17 21:28:42]

lgtm

[jam, 2015-09-17 21:28:43]

lgtm

lgtm

[brettw, 2015-09-17 21:31:55]

The CQ bit was checked by brettw@chromium.org

[commit-bot: I haz the power, 2015-09-17 21:34:19]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1357523003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1357523003/1

[commit-bot: I haz the power, 2015-09-17 21:41:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-09-17 21:43:03]

Patchset 1 (id:??) landed as
https://crrev.com/62ce4f0ee6778343f52682294dc63784b02a7907
Cr-Commit-Position: refs/heads/master@{#349500}