Log Message:
Update "squid31" package to version 3.1.15. Changes since version 3.1.14:
- Regression fix: vhost and defaultsite causing vport to be ignored
- Regression Bug 3295: broken escaping in rfc1738_do_escape
- Bug #3232: fails to compile with OpenSSL v1.0.0
- Bug #3222: cache_peer name is not logging on CONNECT
- Bug #3131: fd_table[fd].closing() assert from
  ConnStateData::noteMoreBodySpaceAvailable()
- Bug #3217: "!fd_table[fd].closing()" from
  ServerStateData::noteMoreBodySpaceAvailable
- Bug #3213: https sites (CONNECT) not open when using NTLM
- Bug #3114: Memory leak in SSL certificate verify code
- Bug #3107: ncsa_auth DES silently truncates passwords to 8 bytes
- Bug #2662: cf_gen failure when cross compiling
- Bug #2655: passing wrong the username to the url_rewrite_program
- Bug #2495: ignore whitespace prefix on config lines
- Bug #2051: 'default' cache_peer option does not match documentation
- Bug #1842: Optimize order of tests in peerWouldBePinged() and
  peerHTTPOkay()
- Bug #1791: timestampsSet does not validate Date: if server sends very
  old date
- Correct parsing of large Gopher indexes
- Enable negative cacheing on unknown or -1 expiry timestamp
- Remove hierarchy_stoplist default value
- Migrate cf_gen tool from C-style to C++
- ... and several documentation and compiler warning fixes