Log Message:
Update squid package to squid-2.5.1nb4.

- include more official squid patches.

   o Make external_acl user names available as IDENT in later acl processing
   o digest authentication security issue
   o external_acl Assertion failed: auth_user_request != NULL
   o make install fails to install icons after make distclean
   o "error: invalid HTTP-ident" breaks log processing