fix tableExists namespace not exists throw exception

Author: JackShi148

src/main/java/com/alipay/oceanbase/hbase/util/OHAdmin.java

@@ -80,7 +80,7 @@ public boolean tableExists(TableName tableName) throws IOException {
                 int errCode = ((ObTableException) cause).getErrorCode();
                 // if the original cause is database_not_exist, means namespace in tableName does not exist
                 // for HBase, namespace not exist will not throw exceptions but will return false
-                if (errCode == ResultCodes.OB_ERR_BAD_DATABASE.errorCode) {
+                if (errCode == ResultCodes.OB_KV_HBASE_NAMESPACE_NOT_FOUND.errorCode) {
                     return false;
                 }
             }