Update clang roll doc.

Update clang roll doc.

Remove trusty32_rel bot. It no longer exists, and 32-bit builds are now
covered by chromium_compile_dbg_32_ng, which is part of the normal
`git cl try` set.

Also remove linux_chromium_gn_dbg which no longer exists because some
of the linux bots use gn by default these days.

BUG=none

Committed: https://crrev.com/86757ab528c281d4b216997f59d07fc2c422744a
Cr-Commit-Position: refs/heads/master@{#363799}

[Nico, 2015-12-08 16:15:29]

thakis@chromium.org changed reviewers:
+ hans@chromium.org

[hans, 2015-12-08 17:12:31]

lgtm

[Nico, 2015-12-08 17:16:00]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-12-08 17:16:38]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1512613002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1512613002/1

[commit-bot: I haz the power, 2015-12-08 21:51:54]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-12-08 21:53:25]

Description was changed from

==========
Update clang roll doc.

Remove trusty32_rel bot. It no longer exists, and 32-bit builds are now
covered by chromium_compile_dbg_32_ng, which is part of the normal
`git cl try` set.

Also remove linux_chromium_gn_dbg which no longer exists because some
of the linux bots use gn by default these days.

BUG=none
==========

to

==========
Update clang roll doc.

Remove trusty32_rel bot. It no longer exists, and 32-bit builds are now
covered by chromium_compile_dbg_32_ng, which is part of the normal
`git cl try` set.

Also remove linux_chromium_gn_dbg which no longer exists because some
of the linux bots use gn by default these days.

BUG=none

Committed: https://crrev.com/86757ab528c281d4b216997f59d07fc2c422744a
Cr-Commit-Position: refs/heads/master@{#363799}
==========

[commit-bot: I haz the power, 2015-12-08 21:53:26]

Patchset 1 (id:??) landed as
https://crrev.com/86757ab528c281d4b216997f59d07fc2c422744a
Cr-Commit-Position: refs/heads/master@{#363799}