Sqlite: Move result count to class declaration

It move the magic number of column results to the sql statement
and improves the mock a little bit.

Change-Id: I101067444cf27ec5dea0c72de7fd484a7e8710f0
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

tests/unit/unittest/sqlitetransaction-test.cpp

@@ -27,9 +27,9 @@
 
 #include "mocksqlitetransactionbackend.h"
 
-#include <sqlitetransaction.h>
+#include <sqlitedatabasemock.h>
 #include <sqliteexception.h>
-#include <mocksqlitedatabase.h>
+#include <sqlitetransaction.h>
 
 namespace {