One test in tst_qfiledialog2 only succeeded if the directory "~/foo"
did not exist. This patch changes the path used to "~/Vugiu1co"
which has hopefully a much lower probability of existing.
The string "Vugiu1co" is taken from a call to "pwgen".
Pick-to: 6.0
Change-Id: Ia82b07902a91eb908a74aa90cdbdf4761d432d9a
Reviewed-by: Karsten Heimrich <karsten.heimrich@qt.io>