CBQE-0: add group EC2 to upgrade conf

Change-Id: I65cb408a087f7e5d7cf6d17251912e8606e00e4f
Reviewed-on: http://review.couchbase.org/27456
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Iryna Mironava <irynamironava@yandex.ru>