Do not use custom reposdir for centos7/LUKS image

opennebula-images/centos7-build-luks-opennebula-image.sh

@@ -79,6 +79,7 @@ mount "${LUKS_DEVICE}" /mnt
 mkdir /mnt/boot
 mount "${LOOPBACK_DEVICE}p1" /mnt/boot
 
+# Add --setopt=reposdir=rpm-repositories if you do not run on CentOS 7.
 dnf -y \
 	--releasever=$RELEASE \
 	--installroot=/mnt \
@@ -86,7 +87,6 @@ dnf -y \
 	--enablerepo=base \
 	--enablerepo=extras \
 	--setopt=install_weak_deps=False install \
-	--setopt=reposdir=rpm-repositories \
 	bash basesystem systemd dnf centos-release cryptsetup dnf
 
 mount --bind /dev /mnt/dev