novatel: fix GSM secondary port enabling after PIN changes

With the PIN changes, the primary port would already be closed
by the time the Novatel modem class was able to send the DMAT
command to enable the secondary ports.  Just try again later.

plugins/mm-modem-novatel-gsm.c

@@ -48,12 +48,26 @@ mm_modem_novatel_gsm_new (const char *device,
 /*    Modem class override functions                                         */
 /*****************************************************************************/
 
+static void
+dmat_callback2 (MMSerialPort *port,
+                GString *response,
+                GError *error,
+                gpointer user_data)
+{
+    mm_serial_port_close (port);
+}
+
 static void
 dmat_callback (MMSerialPort *port,
                GString *response,
                GError *error,
                gpointer user_data)
 {
+    if (error) {
+        /* Try it again */
+        if (mm_serial_port_open (port, NULL))
+            mm_serial_port_queue_command (port, "$NWDMAT=1", 2, dmat_callback2, NULL);
+    } else
         mm_serial_port_close (port);
 }