--use-shared-binary-cache=no still uses cache

[durka]

$ cargo script -e 'panic!()' --use-shared-binary-cache=no
(20986696, 32736, 20986626)
$ cargo script -e 'panic!()' --use-shared-binary-cache=no
(2847947592, 32650, 2847947522)
$ cargo script -e 'panic!()' --use-shared-binary-cache=no
(3250600776, 32680, 3250600706)

This is running some random program I compiled before.