1、提供Maat_cmd_flushDB函数用于重置redis数据库，重置操作后版本号加1。

2、当ZRANGEBYSCORE结果为空的时（日志Got nothing after ），会全量加载。
3、exec_serial_rule事务失败时，重试5次。

src/entry/Maat_rule.cpp

@@ -30,7 +30,7 @@
 #include "stream_fuzzy_hash.h"
 #include "gram_index_engine.h"
 
-int MAAT_FRAME_VERSION_2_1_20180307=1;
+int MAAT_FRAME_VERSION_2_1_20180315=1;
 
 const char* CHARSET_STRING[]={"NONE","gbk","big5","unicode","utf8","bin",
 							"unicode_ascii_esc","unicode_ascii_aligned","unicode_ncr_dec","unicode_ncr_hex","url_encode_gb2312","url_encode_utf8",""};