Added loading tun/tap settings from netconfig. Fix for 793367.

LanItems global config variables for tun/tap devices haven't been
set according existing configuration.
Updated changelog.

Conflicts:
	VERSION
	package/yast2-network.changes
Small refactoring.

Removed useless condition, dead code. Replaced usage of
LanItems::current by getCurrentItem in AddressDialog.

Conflicts:
	src/lan/address.ycp