Change: Only update cf-upgrade when needed

The cf-upgrade binary was broken on 3.6.0 and 3.6.1. The policy to
download a working cf-upgrade binary from the hub is unnecessary when
running newer versions. This change suppresses a promise not kept when
performing upgrades in some cases and reduces unnecessary work.
(cherry picked from commit b95df4848014fb6c5b1485c95cc7000c5f7bf6b2)