Update collectd to 4.10.9.

Too many changes, see changelog:

  https://raw.github.com/collectd/collectd/collectd-4.10/ChangeLog

pkgsrc changes:
- Add support for the zfs_arc plugin (Solaris)
- Add support for the tape plugin (Solaris)
- Add support for curl_json and curl_xml plugins
- Remove libltdl workaround (didn't encounter any problems on NetBSD 6.1)