[master] 40f32e5b2 Fix macos travis job, take 2

[Federico G. Schwindt]

commit 40f32e5b2e1c7af77b7d1833a3fbc8410fd84540
Author: Federico G. Schwindt <fgsch at lodoss.net>
Date:   Sat Mar 7 19:37:58 2020 +0000

    Fix macos travis job, take 2

diff --git a/.travis.yml b/.travis.yml
index b4154d50e..1e236fa82 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -80,6 +80,7 @@ jobs:
           update: true
       before_script:
         - export PATH="/usr/local/opt/sphinx-doc/bin:$PATH"
+        - brew link --overwrite python
         - ./autogen.sh
         - ./configure
       script: *script-common