fix "Conditional jump or move depends on uninitialised value"

+ as reported by valgrind at lines draw.cpp:317 and draw.cpp:781, caused by creation of an uninitialized struct at database.cpp:400
+ fixed==false and ok==false seem like good defaults for this uninitialized struct

wx/draw3/draw.cpp

@@ -752,7 +752,7 @@ void ValuesTable::AddData(DatabaseQuery::ptr q, bool &view_values_changed, bool
 
 }
 
-void ValuesTable::InsertValue(DatabaseQuery::ValueData::V *v, NewValuesInsertStatus &status) {
+void ValuesTable::InsertValue(const DatabaseQuery::ValueData::V *v, NewValuesInsertStatus &status) {
 	DTime dt(m_draw->GetPeriod(), ToWxDateTime(v->time_second, v->time_nanosecond));
 
 	int view_index = m_draw->m_index.GetStartTime().GetDistance(dt);

wx/draw3/include/base_handler.h

@@ -83,31 +83,31 @@ struct DatabaseQuery {
 		PeriodType period_type;
 		struct V {
 			/**Start time of data*/
-			time_t time_second;
-			time_t time_nanosecond;
+			time_t time_second{};
+			time_t time_nanosecond{};
 			/**Custom porobe length*/
-			int custom_length;
+			int custom_length{};
 			/**Response from a database*/
-			double response;
+			double response{};
 			/**First val*/
-			double first_val;
+			double first_val{};
 			/**Last val*/
-			double last_val;
+			double last_val{};
 			/**Sum of probes*/
-			double sum;
+			double sum{};
 			/**Number of valid probes*/
 			int data_count = 0;
 			/**Number of no no-data probes*/
-			int no_data_count;
+			int no_data_count{};
 			/** False if error ocurred during data retrieval*/
-			bool ok;
+			bool ok{false};
 			/** error no*/	
-			int error;
+			int error{};
 			/** Error string*/
-			wchar_t *error_str;
+			wchar_t *error_str{nullptr};
 			/** Fixed value, i.e. it's not gonna change in the future, 
 			    no need to ask for it */
-			bool fixed;
+			bool fixed{false};
 		};
 		std::vector<V> *vv;
 		bool refresh;

wx/draw3/include/draw.h

@@ -226,7 +226,7 @@ struct ValuesTable {
 	 * @param view_updated output param, indiactes if value of any entry wihin @see m_view interval has changed*/
 	void UpdateProbesValues(int idx, bool &stats_updated, bool &view_updated);
 
-	void InsertValue(DatabaseQuery::ValueData::V *v, NewValuesInsertStatus &status);
+	void InsertValue(const DatabaseQuery::ValueData::V *v, NewValuesInsertStatus &status);
 
 	size_t size() const;