don't allow systempreferences to be null

diff --git a/kmig.d/bin/mig-import b/kmig.d/bin/mig-import
index 1edab2c..1788226 100755 (executable)
--- a/kmig.d/bin/mig-import
+++ b/kmig.d/bin/mig-import
@@ -682,8 +682,8 @@ sub restore_preferences {
     my $dom = $parser->parse_file($restore_file);
 
     foreach my $node ($dom->findnodes('//pref')) {
-       my $variable = domain_shift(sql_str($node->findvalue('./variable')));
-        my $value = domain_shift(sql_str($node->findvalue('./value')));
+               my $variable = domain_shift(sql_str_not_null($node->findvalue('./variable')));
+        my $value = domain_shift(sql_str_not_null($node->findvalue('./value')));
         my $query = "UPDATE systempreferences SET value = $value WHERE variable = $variable";
         my $sth = $dbh->prepare($query);
         $sth->execute();