This is needed in order to to proper feature support verification for
IPv6 when configuring the NSVC.
Before this patch, there could be a race condition where NSVC FSM
checked for BTS feature BTS_FEAT_IPV6_NSVC before it was negotiated
through BTS Get Attributes (Ack).
Fixes: OS#4870
Change-Id: I7c207eee0e331995ae04acec014fbd13d4d16280
Before this patch, Get Attributes was sent quicklyafter the OML link
became up, even if the BTS/BB_TRANSC objects were still powered off,
which is wrong since attributes should only be available after the
objects transition out of the Power off state.
Furthermore, information about get attr response already received will
be required in future patches to delay NSVC setting.
Related: OS#4870
Change-Id: I8ec39c7e1f956ffce9aecd58a5590c43200ba086