CI: Fix FreeBSD 15.0 by staying on ALPHA4 due to broken ALPHA5 image

FreeBSD 15.0-ALPHA5 image fails to boot on cloud VMs due to missing
/boot/efi mount point, causing the system to drop to single user mode
where SSH cannot start. Work around this by staying on ALPHA4 and
setting IGNORE_OSVERSION=yes to bypass pkg's kernel version mismatch
prompt during bootstrap. This allows CI to proceed with ALPHA4 until we
have a stable FreeBSD 15.0 image.

Signed-off-by: Ameer Hamza <[email protected]>
Reviewed-by: Brian Behlendorf <[email protected]>
Reviewed-by: Alexander Motin <[email protected]>
Closes openzfs#17846

Author: ixhamza

.github/workflows/scripts/qemu-2-start.sh

@@ -294,7 +294,7 @@ else
   while pidof /usr/bin/qemu-system-x86_64 >/dev/null; do
     ssh 2>/dev/null root@vm0 "uname -a" && break
   done
-  ssh root@vm0 "pkg install -y bash ca_root_nss git qemu-guest-agent python3 py311-cloud-init"
+  ssh root@vm0 "env IGNORE_OSVERSION=yes pkg install -y bash ca_root_nss git qemu-guest-agent python3 py311-cloud-init"
   ssh root@vm0 "chsh -s $BASH root"
   ssh root@vm0 'sysrc qemu_guest_agent_enable="YES"'
   ssh root@vm0 'sysrc cloudinit_enable="YES"'