CBQE-1169: fix swap rebalance sleeps

Change-Id: I796d009587ecdc7aa0995351f1dd6b2b4d39aeaf
Reviewed-on: http://review.couchbase.org/25332
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Deepkaran Salooja <deepkaran.salooja@globallogic.com>
Reviewed-by: Farshid Ghods <farshid@couchbase.com>
Tested-by: Farshid Ghods <farshid@couchbase.com>