Removed duplicated init scripts (suggested by @cjerdonek)

These templates were moved:
* {debian,ubuntu}/supervisor.default -> supervisor.debian.default
* {debian,ubuntu}/supervisor.init -> supervisor.debian.init
* {redhat,centos,fedora}/supervisor.init -> supervisor.redhat.init

Platform specific overrides can now override the templates for their
base platform (for example, a CentOS specific init script would be
placed at centos/supervisor.redhat.init).