The zpool_scrub_002, zpool_scrub_003, zpool_scrub_004 test cases fail
reliably when running against small pools or fast storage. This
occurs because the scrub/resilver operation completes before subsequent
commands can be run.
A one second delay has been added to 10% of zio's in order to ensure
the scrub/resilver operation will run for at least several seconds.
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes#4450