numericalPrecisionPolicy not copied in QSqlDatabase::cloneDatabase()

As in the summary above: QSqlDatabase::cloneDatabase does not copy numericalPrecisionPolicy. I attach a sample code, which leads to:

> ./numericalPrecisionPolicy_during_cloning
db numericalPrecisionPolicy:  0
driver numericalPrecisionPolicy:  0
db2 numericalPrecisionPolicy:  4
driver2 numericalPrecisionPolicy:  4

It's kind of OK in a sense that docs do not promise explicitly that the new connection will have the same precision policy, but I think it is not an expected behaviour (one would expect that the cloned database will have as many connection features the same as the old db as possible).

In my opinion - low priority, because one can add herself/himself a call:

	_db2.setNumericalPrecisionPolicy(_database.numericalPrecisionPolicy());

(where _db2 is the cloned db, and _database is the original database) just after cloning the db connection, but still it would make more sense to have this as a part of standard cloneDatabase(), I think (and if someone does not notice this, she/he will have hard time trying to figure out why the cloned connection leads to results seemingly different from the results from the original connection to the same database...).