Mark blanket offer as transport primary

This is done to ensure the blanket offer is always needed. Marking it as
primary should ensure it always outranks the server network created by
the reserved offer. If the blanket offer receives an onNetworkUnneeded,
the associated reservation is torn down.

Test: TH
Change-Id: I324345884fcf805a06e3251fc51b0ea9ea52b3b7
1 file changed