Update squid3 to 3.5.14 (Squid 3.5.14), security release.

Changes to squid-3.5.14 (16 Feb 2016):

- Bug 4437: Fix Segfault on Certain SSL Handshake Errors
- Bug 4431: C code is not compiled with CFLAGS
- Bug 4418: FlexibleArray compile error with GCC 6
- Bug 4378: assertion failed: DestinationIp.cc:60:
'checklist->conn() && checklist->conn()->clientConnection != NULL'
- Fix invalid FTP connection handling on blocked content
- Fix handling of shared memory left over by Squid crashes or bugs
- Fix mgr:config report 'qos_flows mark' output
- Fix compile error in CPU affinity
- Fix %un logging external ACL username
- Avoid more certificate validation memory leaks
- ... and some documentation updates

(taca)