LU-10717 tests: minor fixes to conf-sanity

LU-10717 tests: minor fixes to conf-sanity

Remove use of fancy quotation marks in conf-sanity test_102.
Quiet other minor shellcheck warnings in test_30a and test_84.
Fix incorrect variable in error message in test_133.

Test-Parameters: trivial testlist=conf-sanity env=ONLY="30a 84 102"
Fixes: aa9f9344fc ("LU-10717 tests: tests should not start mgs")
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I9825157c6b72addc6883e8bc44aea53b483ebbe5
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/53455
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Arshad Hussain <arshad.hussain@aeoncomputing.com>
Reviewed-by: Alexander Boyko <alexander.boyko@hpe.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>