base: ConnectivityServer: Don't reap the new network

When we add a network it may show up as unneeded while we are
adding it and reaped as we are adding it.

Reaping it immediately can happen before the captive portal
check has completed.  This can then cause the network to get added
again causing an unnecessary battery drain.

Change-Id: I837f627c9f6d95bb8a021d2a58f5fc28564ef8b4