USN-5821-2: wheel vulnerability

USN-5821-2: wheel vulnerability

USN-5821-1 fixed a vulnerability in wheel. This update provides
the corresponding update for Ubuntu 16.04 ESM.
Original advisory details:

Sebastian Chnelik discovered that wheel incorrectly handled
certain file names when validated against a regex expression.
An attacker could possibly use this issue to cause a
denial of service.
Source: USN-5821-2: wheel vulnerability