tcp: Revert per-route SACK/DSACK/TIMESTAMP changes.

It creates a regression, triggering badness for SYN_RECV
sockets, for example:

[19148.022102] Badness at net/ipv4/inet_connection_sock.c:293
[19148.022570] NIP: c02a0914 LR: c02a0904 CTR: 00000000
[19148.023035] REGS: eeecbd30 TRAP: 0700   Not tainted  (2.6.32)
[19148.023496] MSR: 00029032 <EE,ME,CE,IR,DR>  CR: 24002442  XER: 00000000
[19148.024012] TASK = eee9a820[1756] 'privoxy' THREAD: eeeca000

This is likely caused by the change in the 'estab' parameter
passed to tcp_parse_options() when invoked by the functions
in net/ipv4/tcp_minisocks.c

But even if that is fixed, the ->conn_request() changes made in
this patch series is fundamentally wrong.  They try to use the
listening socket's 'dst' to probe the route settings.  The
listening socket doesn't even have a route, and you can't
get the right route (the child request one) until much later
after we setup all of the state, and it must be done by hand.

This stuff really isn't ready, so the best thing to do is a
full revert.  This reverts the following commits:

f55017a93f
022c3f7d82
1aba721eba
cda42ebd67
345cda2fd6
dc343475ed
05eaade278
6a2a2d6bf8

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/rtnetlink.h

@@ -368,11 +368,9 @@ enum {
 #define RTAX_MAX (__RTAX_MAX - 1)
 
 #define RTAX_FEATURE_ECN	0x00000001
-#define RTAX_FEATURE_NO_SACK	0x00000002
-#define RTAX_FEATURE_NO_TSTAMP	0x00000004
+#define RTAX_FEATURE_SACK	0x00000002
+#define RTAX_FEATURE_TIMESTAMP	0x00000004
 #define RTAX_FEATURE_ALLFRAG	0x00000008
-#define RTAX_FEATURE_NO_WSCALE	0x00000010
-#define RTAX_FEATURE_NO_DSACK	0x00000020
 
 struct rta_session {
 	__u8	proto;