test: chmod a+rwX the bootc-image-builder artifact

Make the build directory and all its contents world rwXable.  This isn't
needed for the test itself, the artifact is already readable, but the
original permissions make the cleanup of the testing environment fail.

test/scripts/boot-image

@@ -137,6 +137,9 @@ def boot_container(distro, arch, image_type, image_path, manifest_id):
 
             # boot it
             image_name = f"image-boot-test-{distro}-{arch}-{image_type}-" + str(uuid.uuid4())
+
+            # Build artifacts are owned by root. Make them world accessible.
+            testlib.runcmd(["sudo", "chmod", "a+rwX", "-R", tmpdir])
             raw_image_path = f"{tmpdir}/image/disk.raw"
             cmd_boot_aws(arch, image_name, privkey_file, pubkey_file, raw_image_path)