Union builds are not referenced by generated code anymore and have a
number of issues which need to be addressed separately. Just do not
generate them at all, pending a proper factory replacement.
JIRA: MDSAL-49
Change-Id: I6b769ca4d82da16b9f48720e8a17d7c4e1b4e8ef Signed-off-by: Robert Varga <robert.varga@pantheon.tech>