update devel/pcsc-lite to 1.8.20

PR: 215834
Submitted by: Mahdi Mokhtari <mokhi64@gmail.com> (maintainer)
Reviewed by: matthew
Approved by: matthew (mentor)
MFH: 2017Q1
Security: https://vuxml.FreeBSD.org/freebsd/c218873d-d444-11e6-84ef-f0def167eeea.html
Differential Revision: https://reviews.freebsd.org/D9071