I've got the following two available; I assumed to use the "lustre" one consistent with 30.3.2 in the manual; here's what I'm looking at:
[build@lustre-mgs BUILD]$ ls -la
total 16
drwxrwxr-x. 4 build build 4096 Jun 4 17:07 .
drwxrwxr-x. 8 build build 4096 Jun 4 17:00 ..
drwxr-xr-x. 3 build build 4096 Jun 4 17:00 kernel-3.10.0-229.4.2.el7
drwxr-xr-x. 24 build build 4096 Jun 4 17:13 kernel-3.10.0_229.4.2.el7.centos_lustre.x86_64
[build@lustre-mgs BUILD]$ pwd
/home/build/kernel/rpmbuild/BUILD
[build@lustre-mgs BUILD]$
I've been following the build directions explicitly from section 30.2.2 on only correcting for differences between CentOS 7 and RHEL 7 ... everything built clean until now, as far as I can tell. At what point in the build process would I have gone awry for that to happen?