cluster/dht: Check for pointers before de-referencing in dht_stat_merge()
cluster/dht: Check for pointers before de-referencing in dht_stat_merge()

Signed-off-by: Vijay Bellur <vijay@gluster.com>
Signed-off-by: Vijay Bellur <vijay@dev.gluster.com>

BUG: 463 (Crash in dht_stat_merge ())
URL: http://bugs.gluster.com/cgi-bin/bugzilla3/show_bug.cgi?id=463

Kaushikbv/Gluster,Kaushikbv/Gluster,Kaushikbv/Gluster