Timeout changing vucket filter

See MB-5259 ("second" bug).

User-visible behavior is rebalance failing with:

[user:info] [2012-05-10 15:25:36] [ns_1@10.1.3.74:<0.16497.30>:ns_orchestrator:handle_info:246] Rebalance exited with reason {{change_filter_failed,
{'EXIT',
{timeout,
{gen_server,call,
[<0.23092.39>,
start_vbucket_filter_change]}}}},
[

{ns_vbm_sup,change_vbucket_filter,4}

,

{ns_vbm_sup,'-set_replicas/3-fun-2-',5}

,

{lists,foldl,3}

,

{ns_vbm_sup,set_replicas,3}

,

{ns_vbm_sup,'-set_replicas/2-fun-1-',3}

,

{lists,foreach,2}

,

{ns_vbm_sup,apply_changes,2}

,

{ns_vbucket_mover,sync_replicas,0}

]}