Allow TXT records on CHAOS qclass (#321)

Some DNS servers intentionally "misuse" the obsoleted CHAOS (CH) qclass to provide things like `version.bind`, `version.server`, `authors.bind`, `hostname.bind` and `id.server`.

C-ares was not allowing such use cases.

Fix By: Teemu R. (@rytilahti)

ares_parse_txt_reply.c

@@ -113,7 +113,7 @@ ares__parse_txt_reply (const unsigned char *abuf, int alen,
         }
 
       /* Check if we are really looking at a TXT record */
-      if (rr_class == C_IN && rr_type == T_TXT)
+      if ((rr_class == C_IN || rr_class == C_CHAOS) && rr_type == T_TXT)
         {
           /*
            * There may be multiple substrings in a single TXT record. Each