CBD-946:  healthchecker now has 2.1.0 branch

Change-Id: I1500bef7d8d16041bd715ce83ea8228547a5016c
Reviewed-on: http://review.couchbase.org/26956
Reviewed-by: Philip Labee <philip@couchbase.com>
Tested-by: Philip Labee <philip@couchbase.com>