删除无用代码

git-svn-id: http://code.alibabatech.com/svn/druid/trunk@127 b9813039-fb51-4c41-a8b9-e21c2acb5095

src/main/java/com/alibaba/druid/sql/parser/SQLExprParser.java

@@ -179,13 +179,10 @@ public class SQLExprParser extends SQLParser {
                 sqlExpr = new SQLNCharExpr(lexer.stringVal());
                 lexer.nextToken();
                 break;
-            case USR_VAR:
+            case VARIANT:
                 sqlExpr = new SQLVariantRefExpr(lexer.stringVal());
                 lexer.nextToken();
                 break;
-            case SYS_VAR:
-                // QS_TODO add support for system var
-                break;
             case CASE:
                 SQLCaseExpr caseExpr = new SQLCaseExpr();
                 lexer.nextToken();