Wireshark Qt: Fix recent (update the list of file when quit Wireshark)

Change-Id: I2fac5178fca9675ffb70a942d094335323358d22
Reviewed-on: https://code.wireshark.org/review/2825
Reviewed-by: Evan Huus <eapache@gmail.com>
Reviewed-by: Anders Broman <a.broman58@gmail.com>