autobug, prevent redundant notifcations from onConnectChanged

app/src/main/java/com/geeksville/mesh/service/SafeBluetooth.kt

@@ -164,7 +164,12 @@ class SafeBluetooth(private val context: Context, private val device: BluetoothD
             status: Int,
             newState: Int
         ) = exceptionReporter {
+
+            if (gatt == null)
+                info("No gatt: ignoring connection state $newState, status $status") // Probably just shutting down
+            else {
                 info("new bluetooth connection state $newState, status $status")
+
                 when (newState) {
                     BluetoothProfile.STATE_CONNECTED -> {
                         state =
@@ -223,6 +228,7 @@ class SafeBluetooth(private val context: Context, private val device: BluetoothD
                     }
                 }
             }
+        }
 
         override fun onServicesDiscovered(gatt: BluetoothGatt, status: Int) {
             // For testing lie and claim failure
@@ -619,11 +625,12 @@ class SafeBluetooth(private val context: Context, private val device: BluetoothD
 
         failAllWork(BLEException("Connection closing"))
 
-        if (gatt != null) {
+        gatt?.let { g ->
             info("Closing our GATT connection")
-            gatt!!.disconnect()
-            gatt!!.close()
-            gatt = null
+            gatt =
+                null // Clear this first so the onConnectionChange callback can ignore while we are shutting down
+            g.disconnect()
+            g.close()
         }
     }