Adress CVE-2017-6410 in devel/kf5-kio and x11/kdelibs4

Using a malicious PAC file, and then using exfiltration methods in the PAC
function FindProxyForURL() enables the attacker to expose full https URLs.

This is a security issue since https URLs may contain sensitive
information in the URL authentication part (user:password@host), and in the
path and the query (e.g. access tokens).

This attack can be carried out remotely (over the LAN) since proxy settings
allow ``Detect Proxy Configuration Automatically''
This setting uses WPAD to retrieve the PAC file, and an attacker who has access
to the victim's LAN can interfere with the WPAD protocols (DHCP/DNS+HTTP)
and inject his/her own malicious PAC instead of the legitimate one.

Reviewed by: mat, rakuco
Approved by: rakuco (mentor), mat (mentor)
Obtained from: https://marc.info/?l=kde-announce&m=148831226706885&w=2
MFH: 2017Q1
Security: CVE-2017-6410
Differential Revision: https://reviews.freebsd.org/D9908