Revert "init: Adding --delete-before rsync option"

This reverts commit 343541ff23fc73e11d93d0d5c1ba3c868ff7764c.

I do revert it as :
- its useless since we don't manage any update this way
- it does generate weird errors like :

	Copying files from 172.30.4.111:873::install/U12.04-G.2.0.0/ceph...rsync: delete_file:
	rmdir(var/lib/ceph/osd/ceph-2) failed: Device or resource busy (16)
	rsync: delete_file: rmdir(var/lib/ceph/osd/ceph-1) failed: Device or resource busy (16)
	rsync: delete_file: rmdir(var/lib/ceph/osd/ceph-0) failed: Device or resource busy (16)
	rsync: delete_file: rmdir(var/lib/ceph/osd/ceph--1) failed: Device or resource busy (16)
	cannot delete non-empty directory: var/lib/ceph/osd
	cannot delete non-empty directory: var/lib/ceph/osd
	cannot delete non-empty directory: var/lib/ceph

This useless patch got also spotted by Frederic Lepied.
So let's revert it.