BUGFIX:修复expr_plus类型扫描误命中bug，原因是进行MAAT_SET_SCAN_DISTRICT时，如果district不存在，导致本次扫描时，错误的使用上次的district_id，进而误命中。

src/entry/Maat_api.cpp

@@ -1560,6 +1560,7 @@ int Maat_set_scan_status(Maat_feather_t feather,scan_status_t* mid,enum MAAT_SCA
 			if(map_ret<0)
 			{
 				//May be the district is not effected yet.
+				_mid->district_id=-1;
 			}
 			_mid->is_set_district=1;
 			break;

src/entry/Maat_rule.cpp

@@ -28,7 +28,7 @@
 #include "mesa_fuzzy.h"
 #include "great_index_engine.h"
 
-int MAAT_FRAME_VERSION_1_8_20170111=1;
+int MAAT_FRAME_VERSION_1_8_20170217=1;
 const char *maat_module="MAAT Frame";
 
 const char* CHARSET_STRING[]={"NONE","gbk","big5","unicode","utf8","bin",