INFO: mock.py version 1.2.17 starting (python version = 2.7.5)...
Start: init plugins
INFO: selinux enabled
Finish: init plugins
Start: run
INFO: Start(//tmp/tmpRDbxNl/libvirt-3.2.0-14.el7_4.7.src.rpm)  Config(libvirt-3.2.0-14.el7_4.7-20180105120253-421)
Start: clean chroot
Finish: clean chroot
Start: chroot init
INFO: calling preinit hooks
Mock Version: 1.2.17
INFO: Mock Version: 1.2.17
Start: yum install
Finish: yum install
Finish: chroot init
INFO: Installed packages:
Start: build phase for libvirt-3.2.0-14.el7_4.7.src.rpm
Start: build setup for libvirt-3.2.0-14.el7_4.7.src.rpm
ERROR: Exception(//tmp/tmpRDbxNl/libvirt-3.2.0-14.el7_4.7.src.rpm) Config(libvirt-3.2.0-14.el7_4.7-20180105120253-421) 0 minutes 40 seconds
INFO: Results and/or logs in: /srv/reimzul//results/c7.1708.u.ppc64/libvirt/20180105120253/3.2.0-14.el7_4.7.ppc/
INFO: Cleaning up build root ('cleanup_on_failure=True')
Start: clean chroot
Finish: clean chroot
ERROR: Command failed: 
 # /usr/bin/yum-builddep --installroot /var/lib/mock/libvirt-3.2.0-14.el7_4.7-20180105120253-421/root/ /var/lib/mock/libvirt-3.2.0-14.el7_4.7-20180105120253-421/root//builddir/build/SRPMS/libvirt-3.2.0-14.el7_4.7.src.rpm --setopt=tsflags=nocontexts
Getting requirements for libvirt-3.2.0-14.el7_4.7.src
 --> autoconf-2.69-11.el7.noarch
 --> automake-1.13.4-3.el7.noarch
 --> gettext-devel-0.19.8.1-2.el7.ppc64
 --> libtool-2.4.2-22.el7_3.ppc64
 --> Already installed : perl-podlators-2.5.1-3.el7.noarch
 --> git-1.8.3.1-12.el7_4.ppc64
 --> Already installed : 4:perl-5.16.3-292.el7.ppc64
 --> python-2.7.5-58.el7.ppc64
 --> systemd-219-42.el7_4.4.ppc64
 --> libxml2-devel-2.9.1-6.el7_2.3.ppc64
 --> xhtml1-dtds-1.0-20020801.11.el7.noarch
 --> libxslt-1.1.28-5.el7.ppc64
 --> readline-devel-6.2-10.el7.ppc64
 --> ncurses-devel-5.9-14.20130511.el7_4.ppc64
 --> gettext-0.19.8.1-2.el7.ppc64
 --> libtasn1-devel-4.10-1.el7.ppc64
 --> gnutls-devel-3.3.26-9.el7.ppc64
 --> libattr-devel-2.4.46-12.el7.ppc64
 --> libblkid-devel-2.23.2-43.el7_4.2.ppc64
 --> augeas-1.4.0-2.el7_4.2.ppc64
 --> systemd-devel-219-42.el7_4.4.ppc64
 --> libpciaccess-devel-0.13.4-3.1.el7_4.ppc64
 --> yajl-devel-2.0.4-4.el7.ppc64
 --> sanlock-devel-3.5.0-1.el7.ppc64
 --> 14:libpcap-devel-1.5.3-9.el7.ppc64
 --> libnl3-devel-3.2.28-4.el7.ppc64
 --> avahi-devel-0.6.31-17.el7.ppc64
 --> libselinux-devel-2.5-11.el7.ppc64
 --> dnsmasq-2.76-2.el7_4.2.ppc64
 --> iptables-1.4.21-18.2.el7_4.ppc64
 --> radvd-1.9.2-9.el7.ppc64
 --> ebtables-2.0.10-15.el7.ppc64
 --> kmod-20-15.el7_4.6.ppc64
 --> cyrus-sasl-devel-2.1.26-21.el7.ppc64
 --> polkit-0.112-12.el7_3.ppc64
 --> polkit-devel-0.112-12.el7_3.ppc64
 --> Already installed : util-linux-2.23.2-43.el7_4.2.ppc64
 --> libacl-devel-2.2.51-12.el7.ppc64
 --> 10:qemu-img-1.5.3-141.el7_4.4.ppc64
 --> 7:lvm2-2.02.171-8.el7.ppc64
 --> iscsi-initiator-utils-6.2.0.874-4.el7.ppc64
 --> parted-devel-3.1-28.el7.ppc64
 --> 7:device-mapper-devel-1.02.140-8.el7.ppc64
 --> numactl-devel-2.0.9-6.el7_2.ppc64
 --> libcap-ng-devel-0.7.5-4.el7.ppc64
 --> fuse-devel-2.9.2-8.el7.ppc64
 --> netcf-devel-0.2.8-4.el7.ppc64
 --> libcurl-devel-7.29.0-42.el7_4.1.ppc64
 --> audit-libs-devel-2.7.6-3.el7.ppc64
 --> systemtap-sdt-devel-3.1-4.el7_4.ppc64
 --> 1:nfs-utils-1.3.0-0.48.el7_4.ppc64
 --> 1:dbus-devel-1.6.12-17.el7.ppc64
 --> Already installed : gawk-4.0.2-4.el7_3.1.ppc64
 --> scrub-2.5.2-7.el7.ppc64
 --> numad-0.5-17.20150602git.el7.ppc64
http://localhost:11081/bstore/repo/c7.1708.u.ppc64/repodata/04845222df7c030c25a0a96ad8c98454f9b6586c37a0794dcf0aa24b30aa1f8a-filelists.sqlite.bz2: [Errno 14] HTTP Error 404 - Not Found
Trying other mirror.
To address this issue please refer to the below knowledge base article 

https://access.redhat.com/articles/1320623

If above article doesn't help to resolve this issue please create a bug on https://bugs.centos.org/

Error: failure: repodata/04845222df7c030c25a0a96ad8c98454f9b6586c37a0794dcf0aa24b30aa1f8a-filelists.sqlite.bz2 from c7.1708.u.ppc64: [Errno 256] No more mirrors to try.
       http://localhost:11081/bstore/repo/c7.1708.u.ppc64/repodata/04845222df7c030c25a0a96ad8c98454f9b6586c37a0794dcf0aa24b30aa1f8a-filelists.sqlite.bz2: [Errno 14] HTTP Error 404 - Not Found
 You could try using --skip-broken to work around the problem
 You could try running: rpm -Va --nofiles --nodigest