buildah: buildah bud doesn't work from current master on f28 (likely due to overlayfs)

Description

Running buildah bud from master on fedora 28 doesn’t work, and it works fine with buildah 1.6.

Steps to reproduce the issue: Run the demo script: https://github.com/containers/buildah/blob/master/demos/buildah-bud-demo.sh

Describe the results you received:

buildah bud -t buildahbuddemo .
STEP 1: FROM docker://docker.io/fedora:latest
STEP 2: MAINTAINER William Henry
STEP 3: RUN dnf -y update; dnf -y clean all
STEP 4: RUN dnf -y install nginx --setopt install_weak_deps=false; dnf -y clean all                                                                           
STEP 5: RUN echo "daemon off;" >> /etc/nginx/nginx.conf
error building at step {Env:[PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin DISTTAG=f29container FGC=f29 FBR=f29] Command:run Args:[echo "daemon off;" >> /etc/nginx/nginx.conf] Flags:[] Attrs:map[] Message:RUN echo "daemon off;" >> /etc/nginx/nginx.conf Original:RUN echo "daemon off;" >> /etc/nginx/nginx.conf}: error while running runtime: exit status 1

Describe the results you expected: Build should work.

Output of buildah version:

buildah version 1.7-dev (image-spec 1.0.0, runtime-spec 1.0.0)

Output of podman version if reporting a podman build issue:

Version:       1.0.0
Go Version:    go1.10.7
Git Commit:    "327964bfa96f91f39042b87b3e52388f448fd66e"
Built:         Mon Jan 14 20:38:13 2019
OS/Arch:       linux/amd64

Output of cat /etc/*release:

Fedora release 28 (Twenty Eight)

Output of uname -a:

Linux buildah.rdocloud 4.16.3-301.fc28.x86_64 #1 SMP Mon Apr 23 21:59:58 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Output of cat /etc/containers/storage.conf: default config

Output of buildah info:

{
    "host": {
        "Distribution": {
            "distribution": "fedora",
            "version": "28"
        },
        "MemTotal": 8363163648,
        "MenFree": 3868377088,
        "SwapFree": 0,
        "SwapTotal": 0,
        "arch": "amd64",
        "cpus": 4,
        "hostname": "buildah.rdocloud",
        "kernel": "4.16.3-301.fc28.x86_64",
        "os": "linux",
        "rootless": true,
        "uptime": "93h 50m 55.02s (Approximately 3.88 days)"
    },
    "store": {
        "ContainerStore": {
            "number": 0
        },
        "GraphDriverName": "vfs",
        "GraphOptions": null,
        "GraphRoot": "/home/fedora/.local/share/containers/storage",
        "GraphStatus": {},
        "ImageStore": {
            "number": 2
        },
        "RunRoot": "/run/user/1000"
    }
}