LU-11490 tests: use variable for file system name

LU-11490 tests: use variable for file system name

There are several tests that have the file system name
hard coded to "lustre".  These tests will fail or some
calls will fail when these tests are run on systems
where the file system name is not "lustre".  These tests
should be changed to use $FSNAME.

Test-Parameters: trivial testlist=sanity,conf-sanity

Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I22263d2ae5ad29806cb709f462ef21837916c939
Reviewed-on: https://review.whamcloud.com/36694
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Emoly Liu <emoly@whamcloud.com>
Reviewed-by: Wei Liu <sarah@whamcloud.com>