Add hasEverConnected to NetworkStatus object

Add a boolean indicating if we have ever successfully connected to a
network given the current configuration.  This value should be set to
true upon a successful connection and set to false if the credentials
change.  The default value is false.

BUG: 27855896
Change-Id: I1af8f4ad7aac622b48f3c90d88b0debd671a1f40