LU-1625 test: reduce test duration for nfs mode

LU-1625 test: reduce test duration for nfs mode

There isn't much value to run long duration in
nfs mode. Cut down IOR test as well.
Based on original work by Minh Diep.

Test-Parameters: testgroup=parallel-scale-nfsv4
Signed-off-by: Keith Mannthey <keith@whamcloud.com>
Change-Id: Id0c2b23d41a7e0a2763a45747a0f98a24fd77fa7
Reviewed-on: http://review.whamcloud.com/3701
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>