FileSaver: Do not rollback if we never opened the file

This will silence some warnings about removing files with empty
filenames which we get due to trying to remove a file we never
managed to open.

Calling finalize() unconditionally is the right thing to do here
as that processes and/or displays on error message to the user
if there is any.

Change-Id: Ibe7d07233f2c2698e53a7ad21041bc5cc4fcac0e
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Make sure to call FileSaver::finalize

We may leak resources otherwise.

Change-Id: Ic09f58bd47cbf283e22f17f2c3393ca03c5dfacf
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>
Do not pass a file that we know to be broken to QTextStream

Change-Id: I1a593af642c70ca7a0654163e7a32d405a1c2aa6
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@digia.com>