Minor improvement for bug 451735

Bugzilla/DB.pm

@@ -941,8 +941,6 @@ sub bz_drop_index {
         $self->_bz_real_schema->delete_index($table, $name);
         $self->_bz_store_real_schema;        
     }
-
-    return $index_exists ? 1 : 0;
 }
 
 # bz_drop_index_raw($table, $name, $silent)

Bugzilla/DB/Mysql.pm

@@ -772,7 +772,7 @@ sub bz_setup_database {
     # despite it was still present in the DB. That's why we have to
     # force the deletion, bypassing the DB schema.
     if (!$self->bz_index_info('series', 'series_category_idx')) {
-        if (!$self->bz_drop_index('series', 'series_creator_idx')
+        if (!$self->bz_index_info('series', 'series_creator_idx')
             && $self->bz_index_info_real('series', 'series_creator_idx'))
         {
             foreach my $column (qw(creator category subcategory name)) {