LU-18345 test: interop check for sanity-quota 2

LU-18345 test: interop check for sanity-quota 2

The "least qunit" had been renamed to "least_qunit" in 2.15.51,
adding interop handling for it.

Test-Parameters: trivial
Test-Parameters: testlist=sanity-quota env=ONLY=2 serverjob=lustre-master serverbuildno=4586
Fixes: cd1847e73e ("LU-14535 quota: improve quota output format")
Signed-off-by: Hongchao Zhang <hongchao@whamcloud.com>
Change-Id: I1a2cbe66280c2165e0da78ca93605113f9d8e974
Reviewed-on: https://review.whamcloud.com/c/fs/lustre-release/+/56688
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>