LU-15626 tests: Fix shellcheck warning for acceptance-small

LU-15626 tests: Fix shellcheck warning for acceptance-small

This patch addresses the warning and style suggestions
reported by shellcheck. The patch also ensures that
all spaces have been moved to tabs, and the script now
logs what test suites are about to be run.

Signed-off-by: Timothy Day <timday@amazon.com>
Change-Id: Ia88758d0bf89e7d0aa67dfae31d969c780507b88
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/49350
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>