A recent bug  reported as part of the translation effort alerted me to the fact that we have a lot (and I mean a LOT - over 100 per file) of deprecated, unused keys in the various AppErrors files that serve no purpose and just take up space and waste translators time when they examine them.
To make a long story short - I've just merged a patch to remove all these useless messages, and enforce via unit tests that EVERY key there should have a corresponding constant in the EngineMessage or EngineError enums.
Many thanks to my reviewers!
I know this was an tedious patch that couldn't have been too fun to review.
I upgraded my workstation from fc20 to fc21 and had troubles running engine-setup on a 3.5 application.
The following instructions did the trick to me (Thanks to Alon Bar Lev)
1) Download jboss-eap-x.y from http://www.jboss.org/products/eap/overview/ (zip)
2) Extract it to /opt (insure that it has the right permissions)
3) set the following environment variables :
a) export OVIRT_ENGINE_JAVA_HOME=/usr/lib/jvm/jre
b) export OVIRT_ENGINE_JAVA_HOME_FORCE=1
4) run engine-setup as follows :