netfilter: fix the warning on unused refcount variable

net/netfilter/nfnetlink_acct.c: In function 'nfnl_acct_try_del':
net/netfilter/nfnetlink_acct.c:329:15: warning: unused variable 'refcount' [-Wunused-variable]
unsigned int refcount;
             ^

Fixes: b54ab92 ("netfilter: refcounter conversions")
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nfnetlink_acct.c

@@ -326,7 +326,6 @@ static int nfnl_acct_get(struct net *net, struct sock *nfnl,
 static int nfnl_acct_try_del(struct nf_acct *cur)
 {
 	int ret = 0;
-	unsigned int refcount;
 
 	/* We want to avoid races with nfnl_acct_put. So only when the current
 	 * refcnt is 1, we decrease it to 0.