check if ipp service is enabled before the call

Author: zdohnal

firewallsettings.py

@@ -125,6 +125,8 @@ def add_service (self, service):
         except FirewallError as e:
             if e.code is firewall.errors.ALREADY_ENABLED:
                 pass
+            else:
+                raise FirewallError (e.code, e.msg)
 
     def check_ipp_client_allowed (self):
         if not self._get_fw_data ():

newprinter.py

@@ -2306,7 +2306,9 @@ def on_firewall_read (self, data):
     def adjust_firewall_response (self, dialog, response):
         dialog.destroy ()
         if response == Gtk.ResponseType.YES:
-            self.firewall.add_service (firewallsettings.IPP_SERVER_SERVICE)
+            ipp_server_allowed = self.firewall.check_ipp_server_allowed ()
+            if not ipp_server_allowed:
+                self.firewall.add_service (firewallsettings.IPP_SERVER_SERVICE)
             self.firewall.write ()
 
         debugprint ("Fetching network devices after firewall dialog response")