NaCl: Update revision in DEPS, r13974 -> r13987

NaCl: Update revision in DEPS, r13974 -> r13987

This pulls in the following Native Client changes:

r13975: (dschuff) Disable run_dynamic_load_test under nacl_clang x86-32
r13976: (nfullagar) More include path truncation for benchmark source relocation into SDK.
r13977: (bradnelson) Capture build_nexe verbose log messages to emit in the event of error.
r13978: (petarj) [MIPS] Disable seg_gap tests
r13985: (mseaborn) Non-SFI IRT: Remove workarounds for service_runtime/include/ headers
r13986: (dschuff) PNaCl: Update LLVM revision in pnacl/COMPONENT_REVISIONS
r13987: (nfullagar) Nacl-clang does not appear to follow the same portable SIMD vector alignment

BUG=none
TEST=browser_tests and nacl_integration
CQ_EXTRA_TRYBOTS=tryserver.chromium.linux:linux_rel_precise32,linux_nacl_sdk,linux_chromium_dbg
TBR=dschuff@chromium.org

Review URL: https://codereview.chromium.org/675063007

Cr-Commit-Position: refs/heads/master@{#301294}