[Checkins] [zopefoundation/BTrees] eaa1b5: Always build manylinux wheels

[Marius Gedminas]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/BTrees
  Commit: eaa1b50c1bb75efc928408fce0bd40c9bb81376c
      https://github.com/zopefoundation/BTrees/commit/eaa1b50c1bb75efc928408fce0bd40c9bb81376c
  Author: Marius Gedminas <marius at gedmin.as>
  Date:   2019-11-07 (Thu, 07 Nov 2019)

  Changed paths:
    M .manylinux.sh
    M .travis.yml

  Log Message:
  -----------
  Always build manylinux wheels

This PR makes it so we _always_ build manylinux wheels, but only upload
them for git tags.

The diff is messy, for which I apologize.  I had to reformat the YAML to
understand it.  Highlights:

- Moved regular Linux Python builds outside build matrix, for
  conciseness (unfortunately this means 3.6 builds are now done twice:
  once without WITH_COVERAGE and once with)

- Move twine upload from .manylinux.sh into .travis.yml's after_success,
  next to the twine upload used for Mac OS builds

- This means Travis can no longer do an 'exit 0' in before_install, so I
  had to override the install and script sections too

- Move 'docker pull' into the install section so it's not so very empty

- Unify the two calls to twine upload to provide the twine password via
  environment variables instead of command-line or configuration files

- Put related commands inside a single multiline if statement instead of
  repeating the conditions


  Commit: 28a0b56db818ebd511ba32da393385463adef443
      https://github.com/zopefoundation/BTrees/commit/28a0b56db818ebd511ba32da393385463adef443
  Author: Marius Gedminas <marius at gedmin.as>
  Date:   2019-11-07 (Thu, 07 Nov 2019)

  Changed paths:
    M .manylinux.sh
    M .travis.yml

  Log Message:
  -----------
  Merge pull request #115 from zopefoundation/restructure-travis

Restructure Travis to always build manylinux wheels


Compare: https://github.com/zopefoundation/BTrees/compare/aa10755df4af...28a0b56db818