Go's darwin filenames have changed.

32-bit is gone (wasn't being used anyway) and the -osx10.8 suffix is gone.
Still looking into why the Linux bots are unhappy.

Change-Id: If3a35d20fb1cc6f1e3f023d792dc78b5c5aac72a
Reviewed-on: https://boringssl-review.googlesource.com/6061
Reviewed-by: Adam Langley <agl@google.com>
diff --git a/util/bot/go/bootstrap.py b/util/bot/go/bootstrap.py
index 1125619..4a52d9e 100755
--- a/util/bot/go/bootstrap.py
+++ b/util/bot/go/bootstrap.py
@@ -49,8 +49,7 @@
 
 # Platform dependent portion of a download URL. See http://golang.org/dl/.
 TOOLSET_VARIANTS = {
-  ('darwin', 'x86-32'): 'darwin-386-osx10.8.tar.gz',
-  ('darwin', 'x86-64'): 'darwin-amd64-osx10.8.tar.gz',
+  ('darwin', 'x86-64'): 'darwin-amd64.tar.gz',
   ('linux2', 'x86-32'): 'linux-386.tar.gz',
   ('linux2', 'x86-64'): 'linux-amd64.tar.gz',
   ('win32', 'x86-32'): 'windows-386.zip',