Skip `deploy.edge` when looking for branch names for deployment
Skip `deploy.edge` when looking for branch names for deployment

Instead of gathering the branches in `deploy.*.app` key values,
we revert to the old logic of scraping `deploy.*.*`, except
`deploy.edge.*`.
`deploy.edge` is used for dpl testing instead. Using it for
inspecting branch names is wrong, and can lead to
https://github.com/travis-ci/travis-ci/issues/6212.

akoeplinger/travis-build,kevmoo/travis-build,andyli/travis-build,craigcitro/travis-build,jhass/travis-build,JuliaCI/travis-build,kevmoo/travis-build,craigcitro/travis-build,JuliaCI/travis-build,akoeplinger/travis-build,andyli/travis-build,jhass/travis-build