Fix init script and RPM build for CentOS 6

[mbethke]

The RPM for CentOS 6 isn't very useful as is because it installs and init script that looks for the daemon in the wrong place (and thus exists silently without doing anything) and tries to source files that don't exist on CentOS 6, and it doesn't create an account for privilege separation nor the default directories for logs etc.

This fixes a lot of these issues using a few pre- and post-install RPM scripts and a basically rewritten init script.

I'm not completely happy with slapping everything in examples/ and the way this isn't shared with the other RPM-based distributions so while I hope this will make it upstream I'd be happy to improve on it if anyone has suggestions.

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