[DCCP]: Update documentation

As Eddie Kohler points out the RFC is Proposed Standard not experimental.
Also removed documentation about deprecated socket option.

Signed-off-by: Ian McDonald <ian.mcdonald@jandi.co.nz>
Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
1 file changed