Fix NRE in LoadList

Author: mythz

src/ServiceStack.OrmLite/Support/LoadList.cs

@@ -32,13 +32,14 @@ public List<Into> ParentResults
 
         protected LoadList(IDbCommand dbCmd, SqlExpression<From> expr)
         {
-            this.dbCmd = dbCmd;
-            this.expr = expr;
-
             dialectProvider = OrmLiteConfig.DialectProvider;
+
             if (expr == null)
                 expr = dialectProvider.SqlExpression<From>();
 
+            this.dbCmd = dbCmd;
+            this.expr = expr;
+
             var sql = expr.SelectInto<Into>();
             parentResults = dbCmd.ExprConvertToList<Into>(sql);