Ever since commit 12f254fd removed the last parameterization
of gen_err_check(), it no longer makes sense to hide the three
lines of generated C code behind a macro call. Just inline it
into the remaining users.

No change to generated code.
Signed-off-by: NEric Blake <eblake@redhat.com>
Message-Id: <1468468228-27827-7-git-send-email-eblake@redhat.com>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>