Some Dockerfiles (fuse-overlay) require additional devices to be in the
build environment.
This patch allows the user to specify additional devices.
Also I noticed that CapAdd and CapDrop was not working in buildah bud situations,
so this patch also fixes this.
Signed-off-by: Daniel J Walsh <dwalsh@redhat.com>
Closes: #1820
Approved by: @TomSweeneyRedHat