Tests: Fix latency calculation

Idea is to make sure that the FINODELK max latency is not
in the order of seconds.

Change-Id: Ic47dc46c3b2d24d223fe7e2212c4c035de37c9ae
BUG: 895235
Signed-off-by: Pranith Kumar K <pkarampu@redhat.com>
Reviewed-on: http://review.gluster.org/4434
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>