Pin TinyIPA images to stable/2024.2

TinyIPA master branch images are failing with:

    traps: ironic-python-a[495] trap invalid opcode ip:7efee73f58a2 sp:7ffcb6eaf7a8 error:0 in _rust.abi3.so[7efee7112000+631000]

Change-Id: I9e3fe774107fd7fe2bdfeffa5e95dceb8d3d522d

Author: priteau

etc/kayobe/ipa.yml

@@ -79,7 +79,8 @@
 
 # Suffix of upstream Ironic deployment image files. Default is based on
 # {{ openstack_branch }}.
-#ipa_images_upstream_url_suffix:
+# TODO(priteau): Remove once master images are working again
+ipa_images_upstream_url_suffix: "-stable-2024.2"
 
 # Name of Ironic deployment kernel image to register in Glance.
 #ipa_images_kernel_name: