irc/irssi: Update to 1.1.1, Fixes multiple vulnerabilities

Changes: https://irssi.org/NEWS/#v1-1-1

PR: 226001
Submitted by: David O'Rourke <dor.bsd@xm0.uk> (maintainer)
Reported by: tj@mrsk.me (email)
MFH: 2018Q1
Security: 7afc5e56-156d-11e8-95f2-005056925db4