This adds a self-contained function to return the space-separated list of
CCIDs available on the para_server. Visible via 'para_client si'.
Since feature negotiation for CCIDs is supported only from v2.6.30-rc1
(released 7th April 2009), a more recent kernel (>= 2.6.30) is needed to
support this feature, as well as subsequent per-connection use of CCIDs.
Note: This patch still uses a hardcoded upper bound (DCCP_MAX_HOST_CCIDS),
support dynamically detecting the number of CCIDs will be in 2.6.33.