Sometimes logwatch logs will contain URLs and domain names that trip
on abuse lists.    Use a custom filter to remove these checks.

Use newer native "write HTTP" plugin to send metrics to Librato, if configured.

This change set builds collectd from source and configures it in one of
the following ways:

- If Librato credentials are present, collectd will be configured to
send data points to Librato using the collectd-librato plugin.

- If no Librato credentials are present, collectd will be configured to
write RRD files locally (/opt/collectd/var/lib/collectd/rrd by default).

Also mailing to root (which gets forwarded to admin_email) for easier automated sorting