LU-12632 hsm: wait longer in sanity-hsm test_90()

LU-12632 hsm: wait longer in sanity-hsm test_90()

Due to the huge (51) number of HSM requests to be completed we must
wait longer for this test to pass when run using an advanced (zfs)
backend filesystem.

Test-Parameters: trivial fstype=zfs env=ONLY=90 testlist=sanity-hsm,sanity-hsm,sanity-hsm,sanity-hsm,sanity-hsm,sanity-hsm,sanity-hsm,sanity-hsm,sanity-hsm
Signed-off-by: John L. Hammond <jhammond@whamcloud.com>
Change-Id: Ia20086bf5c072c5d120eed5b0937d37d7b4342db
Reviewed-on: https://review.whamcloud.com/40387
Reviewed-by: Ben Evans <beevans@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Nikitas Angelinas <nikitas.angelinas@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>