[DCCP]: Make CCID2 be the default

As per the draft. This fixes the build when netfilter dccp components
are built and dccp isn't. Thanks to Reuben Farrelly for reporting
this.

The following changesets will introduce /proc/sys/net/dccp/defaults/
to give more flexibility to DCCP developers and testers while apps
doesn't use setsockopt to specify the desired CCID, etc.
Signed-off-by: NArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/linux/dccp.h

@@ -320,17 +320,8 @@ static inline unsigned int dccp_hdr_len(const struct sk_buff *skb)
 /* initial values for each feature */
 #define DCCPF_INITIAL_SEQUENCE_WINDOW		100
 #define DCCPF_INITIAL_ACK_RATIO			2
-
-#if defined(CONFIG_IP_DCCP_CCID2) || defined(CONFIG_IP_DCCP_CCID2_MODULE)
 #define DCCPF_INITIAL_CCID			2
 #define DCCPF_INITIAL_SEND_ACK_VECTOR		1
-#elif defined(CONFIG_IP_DCCP_CCID3) || defined(CONFIG_IP_DCCP_CCID3_MODULE)
-#define DCCPF_INITIAL_CCID			3
-#define DCCPF_INITIAL_SEND_ACK_VECTOR		0
-#else
-#error  "At least one CCID must be built as the default"
-#endif
-
 /* FIXME: for now we're default to 1 but it should really be 0 */
 #define DCCPF_INITIAL_SEND_NDP_COUNT		1