altair-lte: update PCO to handle latest VZW deployment

Update PCO handling code such that it conforms to the latest VZW network
behavior. This includes updating the way we mark a SIM as provisioned.
In the old network, only provisioned SIMs can attach to the network.
Now, unprovisioned SIMs can attach and connect to the network.

Change-Id: Ie454f6fb6d8764161f167e93a4235bb93fbde59a

src/mm-broadband-modem.c

@@ -3499,16 +3499,9 @@ modem_3gpp_load_subscription_state (MMIfaceModem3gpp *self,
                                         user_data,
                                         modem_3gpp_load_subscription_state);
 
-   /* Reloading subscription state only occurs on a successfully registered
-    * modem. (Although the 3GPP interface does not reflect this until after
-    * loading operator information completes.)
-    * By default, we can assume that successful registration implies a
-    * provisioned SIM.
-    */
-    mm_dbg ("Load subscription state: Marking the SIM as provisioned.");
     g_simple_async_result_set_op_res_gpointer (
         result,
-        GUINT_TO_POINTER (MM_MODEM_3GPP_SUBSCRIPTION_STATE_PROVISIONED),
+        GUINT_TO_POINTER (MM_MODEM_3GPP_SUBSCRIPTION_STATE_UNKNOWN),
         NULL);
 
     g_simple_async_result_complete_in_idle (result);