Global GIO pool Perf test fix

Change-Id: I2ad0b226cbbdb6f537452db40331f625702146af
Reviewed-on: http://review.couchbase.org/28611
Reviewed-by: abhinav dangeti <abhinav.dangeti@gmail.com>
Tested-by: abhinav dangeti <abhinav.dangeti@gmail.com>