release: Pass PKG_INSTALL_EPOCH (take 2)

We need to pass this to cloudware builds, not just VM builds.

MFC after: 4 days
Fixes: 81ca663642ef ("release: Pass PKG_INSTALL_EPOCH to vmimage.subr")
Sponsored by: Amazon

(cherry picked from commit d14036ea424d5aa3eee20cc6f0b5d7117cc3931b)