LU-13232 tests: add stack_trap to clean up sanity 160j

LU-13232 tests: add stack_trap to clean up sanity 160j

When sanity test 160j fails at any point in the test before
clean up, a client can be left with no file system mounted
or the second file system mount could be left mounted.  We
need to call stack_trap after each of these commands to
clean up the mount points in case of the test failing.

Test-Parameters: trivial
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I631cc2bb2d664a0cdcfe5942d16cd1d011a822ef
Reviewed-on: https://review.whamcloud.com/37550
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Wei Liu <sarah@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>