[XFRM]: Fix policy double put

[XFRM]: Fix policy double put

The policy is put once immediately and once at the error label, which results
in the following Oops:

kernel BUG at net/xfrm/xfrm_policy.c:250!
invalid opcode: 0000 [#2]
PREEMPT
[...]
CPU:    0
EIP:    0060:[<c028caf7>]    Not tainted VLI
EFLAGS: 00210246   (2.6.16-rc3 #39)
EIP is at __xfrm_policy_destroy+0xf/0x46
eax: d49f2000   ebx: d49f2000   ecx: f74bd880   edx: f74bd280
esi: d49f2000   edi: 00000001   ebp: cd506dcc   esp: cd506dc8
ds: 007b   es: 007b   ss: 0068
Process ssh (pid: 31970, threadinfo=cd506000 task=cfb04a70)
Stack: <0>cd506000 cd506e34 c028e92b ebde7280 cd506e58 cd506ec0 f74bd280 00000000
       00000214 0000000a 0000000a 00000000 00000002 f7ae6000 00000000 cd506e58
       cd506e14 c0299e36 f74bd280 e873fe00 c02943fd cd506ec0 ebde7280 f271f440
Call Trace:
 [<c0103a44>] show_stack_log_lvl+0xaa/0xb5
 [<c0103b75>] show_registers+0x126/0x18c
 [<c0103e68>] die+0x14e/0x1db
 [<c02b6809>] do_trap+0x7c/0x96
 [<c0104237>] do_invalid_op+0x89/0x93
 [<c01035af>] error_code+0x4f/0x54
 [<c028e92b>] xfrm_lookup+0x349/0x3c2
 [<c02b0b0d>] ip6_datagram_connect+0x317/0x452
 [<c0281749>] inet_dgram_connect+0x49/0x54
 [<c02404d2>] sys_connect+0x51/0x68
 [<c0240928>] sys_socketcall+0x6f/0x166
 [<c0102aa1>] syscall_call+0x7/0xb

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>