LU-12267 tests: filter trailing '.' for SELinux

LU-12267 tests: filter trailing '.' for SELinux

When SELinux is enforced, sanity test 420 fails due to
the "ls -n" command producing an extra '.' at the end of
the file/directory permissions to indicate extra security
attributes are set.

We need to filter out the trailing '.' in the 'ls -n'
output for testing to pass when SELinux is enabled.

Test-Parameters: trivial envdefinitions=ONLY=420 testlist=sanity
Test-Parameters: clientselinux envdefinitions=ONLY=420 testlist=sanity
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I4a2f199d2ef4a7b1b6a1b381041b384bb0077cc6
Reviewed-on: https://review.whamcloud.com/35026
Tested-by: Jenkins
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Sebastien Buisson <sbuisson@ddn.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>