Revive NetworkInfo's SUSPENDED state.

This got lost in the multinetwork work for L.  It means
that if telephony stops having the ability to pass packets for a while
the rest of the platform doesn't know.

Telephony enters the suspended state if it enters a telephony call
while using certain radio access technologies, or if it switches to
one of those RATs while in a call.  It also can enter this state if
it temporarily loses contact with the network - the modem will
not report the loss of the data call for an indeterminant time in
the hope that regaining the network will restore the connection
without harm to any ongoing ip layer interactions.  For example
passing through a tunnel or taking an elevator trip may use this
mechanism.

bug: 19637156
Change-Id: If9fde68175e8561c19323c81fbfcb02a6e5a00fb