[Python-checkins] travis: Fix macOS build (GH-7250)

[INADA Naoki]

https://github.com/python/cpython/commit/6b87399f0f337d68a71ae55cd9a8667f27a3d2dc
commit: 6b87399f0f337d68a71ae55cd9a8667f27a3d2dc
branch: master
author: INADA Naoki <methane at users.noreply.github.com>
committer: GitHub <noreply at github.com>
date: 2018-06-04T12:57:03+09:00
summary:

travis: Fix macOS build (GH-7250)

Homebrew's python is now python3, but travis preinstalls old python2.
So updated Homebrew requires `brew upgrade python` now.

This commit disables auto update and use preinstalled version of Homebrew.

files:
M .travis.yml

diff --git a/.travis.yml b/.travis.yml
index 204c63fb567d..fc128751cb2a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -60,7 +60,7 @@ matrix:
       env: OPTIONAL=true
       before_install:
         # Python 3 is needed for Argument Clinic and multissl
-        - brew install xz python3
+        - HOMEBREW_NO_AUTO_UPDATE=1 brew install xz python3
         - export PATH=$(brew --prefix)/bin:$(brew --prefix)/sbin:$PATH
     - os: linux
       language: c