lr-wpan: Fix missing PHY initialization (fixes #1174)

Alberto Gallegosrequested to merge
shattered.feelings/ns-3-dev:fixMobilityInit into master

There is a missing m_phy->Initialize(); in the LrWpanNetDevice::DoInitialize(). This causes the mobility model to not be correctly updated in the PHY when using MobilityHelper. The bug was introduced by the recent changes in !2270 (merged).

Merge request reports