imagebuildah: don't walk if rootdir and path are equal
imagebuildah: don't walk if rootdir and path are equal

Signed-off-by: Seth Jennings <sjenning@redhat.com>

Closes: #1256
Approved by: rhatdan

rhatdan/buildah,ipbabble/buildah,projectatomic/buildah,projectatomic/buildah,rhatdan/buildah,nalind/buildah,nalind/buildah-1,nalind/buildah-1,projectatomic/buildah,TomSweeneyRedHat/buildah,TomSweeneyRedHat/buildah,nalind/buildah,ipbabble/buildah,TomSweeneyRedHat/buildah,nalind/buildah-1,rhatdan/buildah