[infra] Fixes for chrome_release_branch

Bug: skia:8932
Change-Id: Ic7414a6fdfbd8f6a822d1c4c09465843889bb885
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/209161
Reviewed-by: Heather Miller <hcm@google.com>
Commit-Queue: Eric Boren <borenet@google.com>
diff --git a/tools/chrome_release_branch.py b/tools/chrome_release_branch.py
index 91205ea..d5e52ed 100644
--- a/tools/chrome_release_branch.py
+++ b/tools/chrome_release_branch.py
@@ -79,13 +79,16 @@
   subprocess.check_call(['new-branch',
                          '--branch', new_branch,
                          '--delete', old_branch,
-                         '--owner', owner])
+                         '--owner', owner,
+                         '--exclude-trybots=chromium.*',
+                         '--exclude-trybots=.*Android_Framework.*'])
 
 
 def main():
   if len(sys.argv) != 2:
     print >> sys.stderr, 'Usage: %s <commit hash for branch>' % sys.argv[0]
     sys.exit(1)
+  go.check()
   branch_at = sys.argv[1]
   m = get_current_milestone()
   new_branch = '%s%d' % (CHROME_REF_PREFIX, m)
diff --git a/tools/infra/go.py b/tools/infra/go.py
index e30540e..213fc75 100644
--- a/tools/infra/go.py
+++ b/tools/infra/go.py
@@ -24,7 +24,7 @@
   try:
     go_exe = subprocess.check_output([WHICH, 'go'])
   except (subprocess.CalledProcessError, OSError):
-    pass
+    go_exe = None
   if not go_exe:
     _fail('Unable to find Golang installation; see '
           'https://golang.org/doc/install')