Add basic support for SuSE Linux

Changes needed for SuSE that were added:
* SuSE requires a different LSB-compliant init script from RHEL
* SuSE required a license header and a shell to be set in the specfile
* SuSE does not have selinux (yay) so I needed to make that conditional
* SuSE's LSB-compliant init script ended up being a mashup of RHEL's and Debian's init script, and was tested with 'service' and /etc/init.d/riak straight away.  The return codes matched [the LSB spec on the topic](http://refspecs.linuxbase.org/LSB_3.1.1/LSB-Core-generic/LSB-Core-generic/iniscrptact.html)