Fixes https://github.com/travis-ci/travis-ci/issues/1840
Fixes https://github.com/travis-ci/travis-ci/issues/1840

When allow_failures contains a nonsensical key-value pair,
we end up having an empty `config` here.
As we all know, `{}.all?` returns `true` no matter what the block.
This results in our allowing every job to fail.

jantman/travis-core,travis-ci/travis-core,developerfm/travis-core,Tiger66639/travis-core,final-ci/travis-core,GistIcon/travis-core,jantman/travis-core,final-ci/travis-core,Tiger66639/travis-core,GistIcon/travis-core,GistIcon/travis-core,kidaa/travis-core,travis-ci/travis-core,final-ci/travis-core,Tiger66639/travis-core,developerfm/travis-core,kidaa/travis-core,kidaa/travis-core,travis-ci/travis-core,developerfm/travis-core