Merge pull request #216 from qinerg/master

使WallFilter可以更准确的获取到数据库类型，并提供对 JDTS 驱动的支持

src/main/java/com/alibaba/druid/wall/WallFilter.java

@@ -54,9 +54,8 @@ public class WallFilter extends FilterAdapter implements WallFilterMBean {
 
     @Override
     public void init(DataSourceProxy dataSource) {
-
         if (this.dbType == null || this.dbType.trim().length() == 0) {
-            this.dbType = dataSource.getDbType();
+            this.dbType = JdbcUtils.getDbType(dataSource.getRawJdbcUrl(), "");
         }
         
         if (dbType == null) {