PNaCl: Update llvm revision in pnacl/COMPONENT_REVISIONS
PNaCl: Update llvm revision in pnacl/COMPONENT_REVISIONS

This pulls in the following LLVM change:

3a2a7d0: (smklein@chromium.org) PNaCl Dynamic Linking: Storing dependencies from command line in PLL.

BUG= https://bugs.chromium.org/p/nativeclient/issues/detail?id=4351
TEST= PNaCl toolchain trybots
TBR=mseaborn@chromium.org

Review URL: https://codereview.chromium.org/1843603003 .

sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client,sbc100/native_client