[Bug 1074861] Add --no-use-wheel to docs and Travis.

This is a partial cherry-pick of
a1b32036209781c555285675e4d53e76408400e3. The difference is that it
doesn't change deployments.

This is mainly because I noticed in #2156 that Travis was failing because it got some wheels instead of tarballs during installation.

This isn't a complete fix for the issue, I don't expect this to close the bug.

r?