CVE-2017-18589: Improper Input Validation in cookie

Affected versions of this crate use the time crate and the method Duration::seconds to parse the Max-Age duration cookie setting. This method will panic if the value is greater than 2^64/1000 and less than or equal to 2^64, which can result in denial of service for a client or server.

This flaw was corrected by explicitly checking for the Max-Age being in this integer range and clamping the value to the maximum duration value.