CBQE-0: uncomment healthcheckertest in 2.2.0-features.conf

Change-Id: I70581a92e0d0bf6fa2e9fbc1bbe6a5409109f365
Reviewed-on: http://review.couchbase.org/28469
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>
Tested-by: Andrei Baranouski <andrei.baranouski@gmail.com>