LU-3089 tests: Give ZFS more time to complete dd's

LU-3089 tests: Give ZFS more time to complete dd's

Due to LU-2887 and ilk, give zfs more time to do disk transfers.  Also
cleanup test formatting.

Signed-off-by: Nathaniel Clark <nathaniel.l.clark@intel.com>
Change-Id: Ia22f2244ccec552046d2efeaeaa6e2194547c96c
Reviewed-on: http://review.whamcloud.com/6217
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Jian Yu <jian.yu@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>