ovs-thread: Fix memory leak in thread exit.

'n' is the number of keys, which are grouped into blocks of L2_SIZE
indexes.  Even if only one key in a block is allocated, the whole block has
a pointer to it that must be freed.  Thus, we need to round up instead of
down.

Reported-at: openvswitch#87
Signed-off-by: Ben Pfaff <[email protected]>
Acked-by: Jarno Rajahalme <[email protected]>

lib/ovs-thread.c

@@ -665,7 +665,7 @@ ovsthread_key_destruct__(void *slots_)
     n = n_keys;
     ovs_mutex_unlock(&key_mutex);
 
-    for (i = 0; i < n / L2_SIZE; i++) {
+    for (i = 0; i < DIV_ROUND_UP(n, L2_SIZE); i++) {
         free(slots->p1[i]);
     }
     free(slots);