Revert "fix bug #706: Use comma to split vmid list when building the crontab vzdump command"

This reverts commit 2fc4c454.

No longer required, because vzdump accepts space separated vmid lists again.

PVE/VZDump.pm

@@ -1266,7 +1266,7 @@ sub command_line {
     my $cmd = "vzdump";
 
     if ($param->{vmid}) {
-	$cmd .= " " . join(',', PVE::Tools::split_list($param->{vmid}));
+	$cmd .= " " . join(' ', PVE::Tools::split_list($param->{vmid}));
     }
 
     foreach my $p (keys %$param) {