allow setting full recovery mode in pre-3.0 clusters

To allow ui to always do setRecoveryType instead of reAddNode

Change-Id: Id8262eaf54cd2fd857c5872c09e60db85c30f02e
Reviewed-on: http://review.couchbase.org/37365
Reviewed-by: Aliaksey Artamonau <aliaksiej.artamonau@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>