typo in janus_rtcp_incoming_transport_cc()

[yin-zhang]

Ran into a couple of typos in janus_rtcp_incoming_transport_cc() in rtcp.c:

			length = (s ? 7 : 14);
			JANUS_LOG(LOG_HUGE, "  [%"SCNu16"] t=status-vector, ss=%s, l=%"SCNu8"\n", num,
				s ? "2-bit" : "bit", length);

should be changed to:

			length = (ss ? 7 : 14);
			JANUS_LOG(LOG_HUGE, "  [%"SCNu16"] t=status-vector, ss=%s, l=%"SCNu8"\n", num,
				ss ? "2-bit" : "bit", length);

That is, s ==> ss. Otherwise the parsing of TWCC packets may get wrong deltas

[atoppi]

@yin-zhang thanks for reporting.

According to the draft:

3.1.4.  Status Vector Chunk

   A status vector chunk starts with a 1 bit to identify it as a vector
   chunk, followed by a symbol size bit and then 7 or 14 symbols,
   depending on the size bit.

        0                   1
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |T|S|       symbol list         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   chunk type (T):  1 bit A one identifies this as a status vector
               chunk.

   symbol size (S):  1 bit A zero means this vector contains only
               "packet received" (0) and "packet not received" (1)
               symbols.  This means we can compress each symbol to just
               one bit, 14 in total.  A one means this vector contains
               the normal 2-bit symbols, 7 in total.

   symbol list:  14 bits A list of packet status symbols, 7 or 14 in
               total.

So length (either 7 or 14) should be set according to the ss variable (that matches the symbol size S of the specs).
Hopefully not a big issue, since we're not doing much with incoming twcc feedback.

Anyway, I'm fixing this asap.