Fix missing bootproto line

Bootproto of new network was overwritten by value in ifcfg file. That
file lacked BOOTPROTO value and therefore it was stated as None value
(not str).

Bootproto was deleted by function _removeConfigValues because deleted
vlan called function vlan.device.remove() -> Nic.remove().

Patchset 4 fixes usecase tested by testAddVlanedBridgeless_oneCommand.

Patchset 6  log ifcfg files that are written
            fixes usecase tested by testAddVlanedBridgeless
            added function isBond() to NetDevice

Patchset 7  removed needless functions removeIfaceCleanup and
            _removeConfigValues
            in _getIfaceConfValues is given priority to network setup
            over current configuration in cfg file

Change-Id: I97ac3464736ac1e8cc4e31cb3a1f5e4db7ee9ebb
Bug-Url: https://bugzilla.redhat.com/980174
Signed-off-by: Petr Sebek <psebek@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/18911
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Tested-by: Dan Kenigsberg <danken@redhat.com>