Various deb package fixups

- Use update-rc.d to have riemann start at boot on Debian
- Similarly, remove the rc.d symlinks in postrm on purge
- Install to /usr/share/riemann rather than /usr/lib/riemann to
  conform to debian policy
- Mark /etc/init.d/riemann as a conf file, also per debian policy
- Add "recommends" relationship with java, as it is needed but not
  everybody installs it as a Debian package.

Change-Id: I4ef98f44bc1fa4f07ddfcd24f7357d9318b13598
Use fakeroot when calling dpkg --build

This way the files inside the deb are owned by uid/gid 0, and lein
still doesn't have to be run within fakeroot.

Change-Id: I33856ba4391c1a95e999451f188ca768a3b8db8b
Start riemann on deb install, stop on remove.

Change-Id: Ife5eafd87de80dfb634453010ed98a3bf794a964