LU-15626 tests: Fix "error" reported by shellcheck for functions.sh

LU-15626 tests: Fix "error" reported by shellcheck for functions.sh

This patch fixes "error" issues reported by shellcheck
for functions.sh. This patch also moves spaces to tabs.

Test-Parameters: trivial
Test-Parameters: testlist=sanity,sanityn
Signed-off-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Change-Id: Iec24ca81b16994c3bfbdc38d8106576a315e0bbd
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/46834
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>