remove display of content mimetype

serv_got_im is triggering an access violation on mimetype with some
systems. This metadata is not necessary and purely informational.

mm-sms.c

@@ -875,8 +875,6 @@ pur_mmsd_receive_message (GVariant *message_t)
 
     char *uri = g_file_get_uri (new);
 
-    serv_got_im (pc, sender, mimetype, PURPLE_MESSAGE_RECV |
-                 PURPLE_MESSAGE_RAW, time (NULL));
     serv_got_im (pc, sender, uri , PURPLE_MESSAGE_RECV |
                  PURPLE_MESSAGE_RAW, time (NULL));