www/squid: fix bug in 4.3, no connections are accepted after ECONNABORTED

• without the fix, squid locks up every couple of hours, no longer accept(2)-ing new connections, and needs to be restarted.

PR: 231950
Submitted by: Mark.Martinec@ijs.si
Reviewed by: Oleh Hushchenkov <gor@clogic.com.ua>
Approved by: Pavel Timofeev <timp87@gmail.com> (maintainer)
Obtained from: https://bugs.squid-cache.org/show_bug.cgi?id=4889