Switch to fedora-29 for fedora-latest nodeset

F28 is EOL as of 5.29.19, so change to use fedora-29
and remove it from stack.sh.

Depends-on: https://review.opendev.org/#/c/662538/
Change-Id: I5ebdb68fcd01a1e63be4b3c0735a274783aad818
2 files changed