Default config paths should be moved to /var/lib/flume

Currently, the default config points to /tmp/ for storage. For example:

<name>flume.master.zk.logdir</name>
<value>/tmp/flume-${user.name}-zk</value>

Instead of /tmp, we should use /var/lib/flume as /tmp will not survive a reboot. This folder should be created and given the appropriate permissions at install time.