LU-10447 tests: deprecate use of $SETSTRIPE/$GETSTRIPE

LU-10447 tests: deprecate use of $SETSTRIPE/$GETSTRIPE

$SETSTRIPE and $GETSTRIPE were needed when we used the
standalone 'lstripe' utility. 'lstripe' hasn't been used
for years and we need to clean up all remnants of it.

Remove the definition and replace all instances of
$SETSTRIPE with '$LFS setstripe' and $GETSTRIPE with
'$LFS getstripe' in test-framework library.

Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: Ibd78b2d75b0b8fc7ff686c1b0a73ce51fe9452e2
Reviewed-on: https://review.whamcloud.com/33925
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>