Fix locate function for SQLite

Author: bahusoid

src/NHibernate/Dialect/SQLiteDialect.cs

@@ -105,6 +105,7 @@ protected virtual void RegisterFunctions()
 			RegisterFunction("current_date", new SQLFunctionTemplate(NHibernateUtil.LocalDate, "datetime(date(current_timestamp, 'localtime'))"));
 
 			RegisterFunction("substring", new StandardSQLFunction("substr", NHibernateUtil.String));
+			RegisterFunction("locate", new StandardSQLFunction("instr",  NHibernateUtil.Int32));
 			RegisterFunction("left", new SQLFunctionTemplate(NHibernateUtil.String, "substr(?1,1,?2)"));
 			RegisterFunction("trim", new AnsiTrimEmulationFunction());
 			RegisterFunction("replace", new StandardSafeSQLFunction("replace", NHibernateUtil.String, 3));