debian: stop sysvinit on ceph.prerm

Signed-off-by: Sage Weil <sage@inktank.com>
os/LevelDBStore: fix compression selection

We were always disabling compression.

Fixes: #5131
Reported-by: Sylvain Munaut <s.munaut@whatever-company.com>
Signed-off-by: Sage Weil <sage@inktank.com>
Merge branch 'next'

Conflicts:
	debian/ceph.prerm