cli: Show a positive response instead of an error when receiver pairs on already-used slot in CLI

lib/solaar/cli/pair.py

@@ -87,5 +87,9 @@ def run(receivers, args, find_receiver, _ignore):
 		dev = receiver.status.new_device
 		print ('Paired device %d: %s (%s) [%s:%s]' % (dev.number, dev.name, dev.codename, dev.wpid, dev.serial))
 	else:
-		error = receiver.status.get(_status.KEYS.ERROR) or 'no device detected?'
+		error = receiver.status.get(_status.KEYS.ERROR)
+		if error :
 			raise Exception("pairing failed: %s" % error)
+		else :
+			print ('Paired a device') # this is better than an error
+