luna-sysmgr: use --exclude-vcs --exclude-backups for tarballs

rather than --exclude=.svn

Open-webOS-DCO-1.0-Signed-off-by: Eric Blade <eric.blade@palm.com>

Change-Id: Ie054eec24ef9603a59a0d6ce972590d682ffc195
Reviewed-on: http://g2g.palm.com/1290
Reviewed-by: Eric Blade <eric.blade@palm.com>
Tested-by: Eric Blade <eric.blade@palm.com>
Reviewed-by: Build Verification
Reviewed-by: Roger Stringer <roger.stringer@palm.com>