BUG/MINOR: mux-quic: support nul buffer with qc_free_ncbuf()

qc_free_ncbuf() may now be used with a NCBUF_NULL buffer as parameter.
This is useful when using this function on a QCS with no allocated
buffer. This case was not reproduced for the moment, but it will soon
become more present as buffers will be released if emptied.

Also a call to offer_buffers() is added to conform with the dynamic
buffer management of haproxy.
1 file changed