use infinite timeout for takeover gen_server:call

Because 5 seconds is not always enough.

Change-Id: Id04e16c01f9afa6ca48b2a44836869419c54ad63
Reviewed-on: http://review.couchbase.org/33722
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Reviewed-by: Artem Stemkovski <artem@couchbase.com>
Tested-by: Artem Stemkovski <artem@couchbase.com>