Revert of PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS

Revert of PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS (patchset #1 id:1 of https://codereview.chromium.org/1008693005/)

Reason for revert:
This causes a bunch of failures on the PNaCl toolchain waterfall, which seem related to reading bad data from the stack. Reverting.

Original issue's description:
> PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
> 
> This pulls in the following LLVM changes:
> 
> 899d5ab: (stichnot@chromium.org) Allow the LLVM cmake build to use ccache.
> c5f8056: (jfb@chromium.org) ExpandVarArgs: don't pack the vararg struct
> 
> BUG= https://code.google.com/p/nativeclient/issues/detail?id=4102
> TEST= PNaCl toolchain trybots
> TBR= dschuff@chromium.org
> 
> Committed: https://chromium.googlesource.com/native_client/src/native_client/+/84b4c32e4b53a143a8599d26df25a4d5d996c825

TBR=dschuff@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG= https://code.google.com/p/nativeclient/issues/detail?id=4102

Committed: https://chromium.googlesource.com/native_client/src/native_client/+/92ab4d5b322a5b8a69ee8fdf3814fdabd25829e5

[JF, 2015-03-14 15:17:59]

Created Revert of PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS

[commit-bot: I haz the power, 2015-03-14 15:18:07]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1002423002/1

[commit-bot: I haz the power, 2015-03-14 15:18:19]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/native_client/src/native_client/+/92ab4d5b3...

[JF, 2015-03-14 18:07:16]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.chromium.org/1012463002/ by jfb@chromium.org.

The reason for reverting is: I can't repro the failures locally... Flake?.