New VS 2013 toolchain with setenv.*.json

VS 2015 is used for Chromium builds, but having VS 2013 available is
useful, in particular for SDK bots for nacl. This changes the VS 2013
tool set to one that has setenv.*.json files that were made necessary
by crrev.com/1805173002 so that VS 2013 can still be used.

BUG=495204

Review URL: https://codereview.chromium.org/1886493002

Cr-Commit-Position: refs/heads/master@{#387032}

build/vs_toolchain.py

@@ -281,7 +281,7 @@ def _GetDesiredVsToolchainHashes():
     # Update 2.
     return ['95ddda401ec5678f15eeed01d2bee08fcbc5ee97']
   else:
-    return ['4087e065abebdca6dbd0caca2910c6718d2ec67f']
+    return ['03a4e939cd325d6bc5216af41b92d02dda1366a6']
 
 
 def ShouldUpdateToolchain():