Rename `pipe` variables to distinguish launcher -> sup and sup -> launcher
Rename `pipe` variables to distinguish launcher -> sup and sup -> launcher

Addresses review feedback https://github.com/habitat-sh/habitat/pull/5365/files#r204208494

Signed-off-by: Jon Bauman <e6c6a4db54ad11b4de69fed67139594b59f3444f@users.noreply.github.com>

habitat-sh/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat,rsertelon/habitat,habitat-sh/habitat,habitat-sh/habitat,rsertelon/habitat