CNY-1814 - Fix up changeset source so that it doesn't assert when mixing rooted troves and unrooted troves in the same job.  Also fix bug that manifested itself when two relative changesets were included in the same changeset source (this happened after restarts in updates from relative changesets)
CNY-1814 - Fix up changeset source so that it doesn't assert when mixing
rooted troves and unrooted troves in the same job.  Also fix bug
that manifested itself when two relative changesets were included in
the same changeset source (this happened after restarts in updates
from relative changesets)

fedora-conary/conary,fedora-conary/conary,fedora-conary/conary,fedora-conary/conary,fedora-conary/conary