NaCl: Update revision in DEPS, r9707 -> r9715

NaCl: Update revision in DEPS, r9707 -> r9715

This pulls in the following Native Client changes:

r9708: (dschuff) Use separate filenames for real and dummy IRT shims
r9709: (dschuff) Add pnacl clang driver support for specifying frontend triple and float abi
r9710: (jvoung) Pass through files with {.i,.ii} extension (pre-processed) to clang
r9711: (mseaborn) ARM: Remove prototype of non-existent NaClGetThreadCombinedDescriptor()
r9712: (mseaborn) PNaCl: Compile various support files using -Werror
r9713: (mseaborn) Faulted thread queue test: Split main() into smaller functions
r9714: (jvoung) Remove pnacl/test.sh script options to run browser tests since we
r9715: (mseaborn) Thread suspension: Fix querying registers for a corner case on Mac OS X

BUG=none
TEST=nacl_integration

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=156371

[Mark Seaborn, 2012-09-12 20:40:10]

win_rel failures seem to be a result of new, broken compositor tests being added
to the Buildbot config out of band.

[bradn, 2012-09-12 20:41:19]

lgtm