change build.prop to (1) work when on a detached head during jenkins build (2) use bash compatible property key names and (3) include shell git info
use ls-remote to compare HEAD and then reflog as a backup
fix returning reflog promise
allow shell git info to be optional
Merge branch 'master' into jasonsanjose/build-prop-keys
Merge branch 'master' into jasonsanjose/build-prop-keys
build-config task to be used by concat/minify build process
Merge pull request #6076 from adobe/jasonsanjose/build-prop-keys

Changes to build.prop file to support Jenkins jobs