Update www/squid30 package to 3.0.20 (3.0.STABLE20).

Changes to squid-3.0.STABLE20 (29 Oct 2009):

- Bug 2794: ESI parsing on FreeBSD
- Bug 2791: assertion failed: MemBuf.cc:400: new_cap > (size_t) capacity
- Bug 2779: Support GNU/kFreeBSD
- Bug 2773: Segfault in RFC2069 Digest authantication
- Bug 2768: squid_ldap_group argument parsing error
- Bug 2761: Gopher and double HTTP response header
- Bug 2735: Incomplete -fhuge-objects detection
- Bug 2722: prevent CONNECT via http_port with accel
- Bug 2624: Invalid response for IMS request
- Bug 2510: digest_ldap_auth TLS support
- Correct LINUX_CAPABILITY actions on non-Linux

(taca)