netfilter: fix warning in ebt_ulog init function.

The ebt_ulog module does not follow the fixed convention about function
return. Loading the module is triggering the following message:

sys_init_module: 'ebt_ulog'->init suspiciously returned 1, it should follow 0/-E convention
sys_init_module: loading module anyway...
Pid: 2334, comm: modprobe Not tainted 2.6.29-rc5edenwall0-00883-g199e57b #146
Call Trace:
 [<c0441b81>] ? printk+0xf/0x16
 [<c02311af>] sys_init_module+0x107/0x186
 [<c0202cfa>] syscall_call+0x7/0xb

The following patch fixes the return treatment in ebt_ulog_init()
function.

Signed-off-by: Eric Leblond <eric@inl.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>