net/libzmq4: Update to 4.3.4, Fix security issues

- Patches removed were incorporated upstream.

Changelog:  https://github.com/zeromq/libzmq/releases/tag/v4.3.2
      https://github.com/zeromq/libzmq/releases/tag/v4.3.3
      https://github.com/zeromq/libzmq/releases/tag/v4.3.4



PR:		255102
Approved by:	koobs (maintainer, implicit)
MFH:		2021Q2
Security:	21ec4428-bdaa-11eb-a04e-641c67a117d8
Security:	6954a2b0-bda8-11eb-a04e-641c67a117d8

Co-authored-by: Danilo G. Baio <dbaio@FreeBSD.org>