ask os_info for observers. fixes #2476. the same happens (and cannot be fixed)...

ask os_info for observers. fixes #2476. the same happens (and cannot be fixed) for invisible, but how often we ask os info on invisible people? (and also that can betray their invisibility eventhough it is their client that hsould not reply if they are invisible. anyways..)

src/vcard.py

@@ -296,8 +296,10 @@ class VcardWindow:
 		gajim.connections[self.account].request_last_status_time(self.contact.jid,
 			self.contact.resource)
 
-		# do not wait for os_info if contact is not connected
-		if self.contact.show in ('offline', 'error'):
+		# do not wait for os_info if contact is not connected or has error
+		# additional check for observer is needed, as show is offline for him
+		if self.contact.show in ('offline', 'error')\
+		and not self.contact.is_observer():
 			self.os_info_arrived = True
 		else: # Request os info if contact is connected
 			gobject.idle_add(gajim.connections[self.account].request_os_info,