1022646 - remove units_path; in 2.3, it's method.
scrap manifest migration.  not worth the effort.
download manifest to a separate path.
Merge (-s ours) pulp-2.2 => pulp-2.3, post-build
Merge pull request #710 from pulp/jortel-1022646

1022646 - nodes manifest migration fails on 2.2 to 2.3 upgrades
Merge commit '9068c7c8dcb0ec96793f4f30fc15edcba2e3bcd7'