Fix Stmt:Data object leak

call Stmt::destroyData() whenever a Stmt object is to be removed in
BasicBlock to delete the Stmt::Data object hold in the Stmt object.

Change-Id: I59c939d79b935153e6f8613e54f149120f5198f5
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Reviewed-by: Erik Verbruggen <erik.verbruggen@digia.com>
Fix copy-paste errors.

Fix two copy-paste errors identified by static analysis at
http://www.viva64.com/en/b/0251/

Change-Id: I359a4635a4a837995f9ed9bf0182a1ca543725df
Reviewed-by: Daniel Molkentin <daniel@molkentin.de>
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>
Merge remote-tracking branch 'origin/stable' into 5.3

Change-Id: Id783915b0139a90ecfb99f8298b1ff5cf506a1dd