Restore interface selection after interface refresh

Restore interface selection after interface refresh

Remember which interfaces were selected for the next capture and restore
the selection (note that only active capture devices are stored in
"ifaces", so simply querying that list does not work).

The original change tried to fix duplicate devices (which were added
from "ifaces" to "all_ifaces") by clearing "ifaces", this patch tries to
fix that by ignoring all non-PIPE devices while preserving "ifaces".

Now after refreshing the interfaces list in Qt, the selection in the
Manage Interfaces dialog is preserved. Removal of the bluetooth0
interface+refresh does hide the interface. Read+refresh does add the
interface (and preserve the selected state).

Change-Id: I26a78982f0327c835dc96da9c813e38f31d6cd3d
Fixes: v1.99.0-rc1-879-g55733ea170 ("fix scan_local_interfaces()")
Reviewed-on: https://code.wireshark.org/review/20477
Petri-Dish: Peter Wu <peter@lekensteyn.nl>
Tested-by: Petri Dish Buildbot <buildbot-no-reply@wireshark.org>
Reviewed-by: Stig Bjørlykke <stig@bjorlykke.org>
Reviewed-by: Anders Broman <a.broman58@gmail.com>