use ∞ timeout for mc_client_binary:compact_vbucket

Because we expect it to take very long time.

Change-Id: I786a13153067a65f2ea28b781c040314520fa37b
Reviewed-on: http://review.couchbase.org/33808
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>