Pop3-client bugfixes (mostly).

* libmailutils/stream/fltstream.c (filter_ctl): MU_IOCTL_TRANSPORT
returns filter transport stream.
* libproto/pop/pop3_rdlist.c (mu_pop3_stream_to_list): Make sure
status is initialized and reflects the actual status.
* libproto/pop/pop3_stream.c (mu_pop3_filter_create): Do not unref
transport stream, it is done by the caller.

@@ -407,8 +407,11 @@ filter_ctl (struct _mu_stream *stream, int code, int opcode, void *ptr)
 	      ptrans[1] = NULL;
 	    }
 	  break;
+	default:
+	  return ENOSYS;
 	}
-      /* fall through */
+      break;
+      
     default:
       return mu_stream_ioctl (fs->transport, code, opcode, ptr);
     }

@@ -33,7 +33,8 @@ mu_pop3_stream_to_list (mu_pop3_t pop3, mu_stream_t stream, mu_list_t list)
   int status;
   size_t n;
   
-  while (mu_stream_getline (stream, &pop3->rdbuf, &pop3->rdsize, &n) == 0
+  while ((status = mu_stream_getline (stream, &pop3->rdbuf, &pop3->rdsize, &n))
+	 == 0
 	 && n > 0)
     {
       char *np = strdup (pop3->rdbuf);

@@ -74,7 +74,6 @@ mu_pop3_filter_create (mu_stream_t *pstream, mu_stream_t stream)
 
   rc = mu_filter_create (pstream, stream, "CRLFDOT", MU_FILTER_DECODE,
 			 MU_STREAM_READ);
-  mu_stream_unref (stream);
   if (rc == 0)
     {
       struct mu_pop3_stream *sp = (struct mu_pop3_stream *) stream;