docker-base: Start shipping fstab again

Even though it's silly, the ImageFactory-in-Koji use case calls into
libguestfs to introspect the target system, and libguestfs relies on
/etc/fstab to detect installed operating systems.

fedora-docker-base.ks

@@ -59,6 +59,5 @@ sed -i 's/OOMScoreAdjust=-900//' /etc/systemd/system/dbus.service
 systemctl mask systemd-remount-fs.service dev-hugepages.mount sys-fs-fuse-connections.mount systemd-logind.service getty.target console-getty.service
 
 rm -f /etc/machine-id
-rm -f /etc/fstab
 
 %end