Redmine#5986: fix to assume all non-specified return codes are failed
Merge pull request #1737 from tzz/bugfix/redmine5987-unspecified-return-codes-are-repaired

Redmine#5986: fix to assume all non-specified return codes are failed
Set this.promiser immediately after promiser expansion per iteration.

HACK: except for files and storage promises.
Unstage acceptance test.
Close #5959.
Redmine#5981: add dcs.cf.sub and plucked.cf.sub to distributed files
Redmine#5981: clarify --gainroot=env