Handle BTS/BBTRANSC Get Attributes (Ack) in NM FSMs

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
7 files changed