The tez rpm can not be built. After some self hacks I finally figured out the root cause:
BIGTOP-1179 commit is weird. The commit message shows that it was authored on 27 Nov 2014, which should be an old patch targeted on 0.5.2 instead of the new one authored by oflebbe. The wired thing is that the tez version of that commit is 0.6.0, which is new, but the code in that commit looked the same as the old patch submitted on 27 Nov 2014.
Anyhow, we need to sync up the code to the final reviewed version in