PNaCl: Update LLVM revision in pnacl/DEPS
PNaCl: Update LLVM revision in pnacl/DEPS

This pulls in the following LLVM changes:

81aece3: (mseaborn@chromium.org) PNaCl: Strip more unwanted attributes: "align" on functions and "unnamed_addr"
c31b941: (dschuff@chromium.org) Fix PrologEpilogInserter to save and restore all callee saved registers if the function calls _builtin_unwind_init()

BUG= https://code.google.com/p/nativeclient/issues/detail?id=3486
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3415
TEST=PNaCl toolchain trybots
R=mseaborn@chromium.org

Review URL: https://codereview.chromium.org/17059008

git-svn-id: 721b910a23eff8a86f00c8fd261a7587cddf18f8@11550 fcba33aa-ac0c-11dd-b9e7-8d5594d729c2

Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client,Lind-Project/native_client