Extract PPC64LE into script and port to Python.

.travis.yml

@@ -39,15 +39,7 @@ jobs:
 cache: pip
 
 before_install:
-  - |
-    # Except on bionic, Travis Linux base image for PPC64LE
-    # platform lacks the proper
-    # permissions to the directory ~/.cache/pip/wheels that allow
-    # the user running travis build to install pip packages.
-    # TODO: is someone tracking this issue? Maybe just move to bionic?
-    if [[ "$TRAVIS_CPU_ARCH" == "ppc64le" ]]; then
-      sudo chown -Rfv $USER:$GROUP ~/.cache/pip/wheels
-    fi
+- python tools/ppc64le-patch.py
 
 install:
 

tools/ppc64le-patch.py

@@ -0,0 +1,28 @@
+"""
+Except on bionic, Travis Linux base image for PPC64LE
+platform lacks the proper
+permissions to the directory ~/.cache/pip/wheels that allow
+the user running travis build to install pip packages.
+TODO: is someone tracking this issue? Maybe just move to bionic?
+"""
+
+import subprocess
+import collections
+import os
+
+
+def patch():
+    env = collections.defaultdict(str, os.environ)
+    if env['TRAVIS_CPU_ARCH'] != 'ppc64le':
+        return
+    cmd = [
+        'sudo',
+        'chown',
+        '-Rfv',
+        '{USER}:{GROUP}'.format_map(env),
+        os.path.expanduser('~/.cache/pip/wheels'),
+    ]
+    subprocess.Popen(cmd)
+
+
+__name__ == '__main__' and patch()