MB-6983: proper quantity format for large graph

Change-Id: I2a1afdb0918aa760b6afe05a79e1366e159ec236
Reviewed-on: http://review.couchbase.org/33795
Reviewed-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>
Tested-by: Aliaksey Kandratsenka <alkondratenko@gmail.com>