[MINOR] Free stick table pool on denint()

The motivation for this is that when soft-restart is merged
it will be come more important to free all relevant memory in deinit()

Discovered using valgrind.
diff --git a/src/haproxy.c b/src/haproxy.c
index da9f8c6..f982727 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -874,6 +874,7 @@
 		pool_destroy2(p->req_cap_pool);
 		pool_destroy2(p->rsp_cap_pool);
 		pool_destroy2(p->hdr_idx_pool);
+		pool_destroy2(p->table.pool);
 
 		p0 = p;
 		p = p->next;