enable ssl

Squid3 is not accepting https requests, with reason.

`squid3 -k parse` reveals

Processing: https_port 8889 cert=/etc/squid3/ssl/local.lan.crt key=/etc/squid3/ssl/local.lan.key
ERROR: 'https_port' requires --enable-ssl

please add --enable-ssl to future builds unless there's a reason it's being omitted.

required information:
-----
lsb_release -rd
Description: Ubuntu 14.10
Release: 14.10
-----
apt-cache policy squid3
squid3:
  Installed: 3.3.8-1ubuntu8.1
  Candidate: 3.3.8-1ubuntu8.1
  Version table:
 *** 3.3.8-1ubuntu8.1 0
        500 http://us.archive.ubuntu.com/ubuntu/ utopic-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ utopic-security/main amd64 Packages
        100 /var/lib/dpkg/status
     3.3.8-1ubuntu8 0
        500 http://us.archive.ubuntu.com/ubuntu/ utopic/main amd64 Packages

i do feel that omitting SSL from configuration during build is a security risk and as such i am marking it as a security vulnerability.

thank you