NaCl: Update revision in DEPS, r14008 -> r14019

This pulls in the following Native Client changes:

r14010: (shyamsundarr) allow 16 bit xadd (including atomic version) in ia32.
r14013: (hidehiko) Non-SFI mode: Add MSG_TRUNC and MSG_CTRUNC to sys/socket.h
r14014: (yyanagisawa) Exponential backoff sleep time on WindowsError.
r14015: (shyamsundarr) enable 16 bit cmpxchg in ia32.
r14017: (maruel) Normalize paths in pnacl/driver/driver_tools.py.
r14019: (mcgrathr) toolchain_build: Switch gcc to 4.9 branch

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

Review URL: https://codereview.chromium.org/698973002

Cr-Commit-Position: refs/heads/master@{#302535}

DEPS

@@ -96,7 +96,7 @@ vars = {
   # Three lines of non-changing comments so that
   # the commit queue can handle CLs rolling NaCl
   # and whatever else without interference from each other.
-  'nacl_revision': 'f524a5feca4b30d8cf3a95e472e1e9e44d537213', # from svn revision r14008
+  'nacl_revision': 'b3e7d9353e64cd00250d02fb5edfcc65be0a941a', # from svn revision r14019
 }
 
 # Only these hosts are allowed for dependencies in this DEPS file.