ci: work around various broken aspects of Travis VM image

- Symlink broken Ubuntu Python package pieces back together. See many
  Google hits about this issue.
- Remove apt sources that can no longer be updated.

.ci/ansible_tests.py

@@ -63,6 +63,8 @@ with ci_lib.Fold('job_setup'):
         run("sudo apt-get update")
         run("sudo apt-get install -y sshpass")
 
+    run("bash -c 'sudo ln -vfs /usr/lib/python2.7/plat-x86_64-linux-gnu/_sysconfigdata_nd.py /usr/lib/python2.7 || true'")
+    run("bash -c 'sudo ln -vfs /usr/lib/python2.7/plat-x86_64-linux-gnu/_sysconfigdata_nd.py $VIRTUAL_ENV/lib/python2.7 || true'")
 
 with ci_lib.Fold('ansible'):
     playbook = os.environ.get('PLAYBOOK', 'all.yml')

.travis.yml

@@ -16,6 +16,7 @@ cache:
   - /home/travis/virtualenv
 
 install:
+- grep -Erl git-lfs\|couchdb /etc/apt | sudo xargs rm -v
 - .ci/${MODE}_install.py
 
 script: