[wesnoth_addon_manager] Properly encode description strings...

...when uploading a campaign.

data/tools/wesnoth/wmldata.py

@@ -268,6 +268,7 @@ class DataSub(Data):
         for r in result:
             if r != None:
                 # For networking, we need actual bytesteam here, not unicode.
+                if type(r) is unicode: r = r.encode("utf8")
                 bytes += str(r)
 
         return bytes