LU-6051 utils: Remove incorrect request for getstripe help

LU-6051 utils: Remove incorrect request for getstripe help

The option flag for stripe-size in the getstripe command was changed
in Lustre 1.8.  To detect the correct flag to use, the help was
parsed.  However, the help was incorrectly invoked by using the
"--help" option, instead of the correct "lfs help getstripe".
Since interoperability with 1.8 is no longer needed, the incorrect
code is removed and the correct flag is hard-coded.

Test-Parameters: trivial
Signed-off-by: Steve Guminski <stephenx.guminski@intel.com>
Change-Id: I29ae644c7d6b2ed247573d83c943cb556cfb6325
Reviewed-on: https://review.whamcloud.com/28597
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>