LU-4298 utils: do not create file with no striping info

'lfs setstripe' should not create a file with no striping
information if bad values are given. The input parameter
check in llapi_file_open_pool is moved before the file open
to catch bad parameters before the file is created.

A check is added to sanity test 27f to make sure
'lfs setstripe -s' does not create a file with no
striping information.

Signed-off-by: Sebastien Buisson <sebastien.buisson@bull.net>
Signed-off-by: James Nunez <james.a.nunez@intel.com>
Change-Id: I19beef973dc3a62bf2cb443e02195896772702fc
Reviewed-on: http://review.whamcloud.com/8375
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>