LU-8066 tests: don't access /proc/sys/lnet/debug directly

LU-8066 tests: don't access /proc/sys/lnet/debug directly

In replay-single test_70e use "lctl set_param" to set the debug mask
rather than writing into the /proc/sys/lnet/debug file directly, since
this tunable moved to sysfs in commit v2_10_51_0-12-g7092309f32.

Clean up the test code style in test_70e as well.

Test-Parameters: trivial testlist=replay-single
Signed-off-by: Andreas Dilger <adilger@whamcloud.com>
Change-Id: I65c2bd9643fc6fc54a5de7b6404d316c0ff12537
Reviewed-on: https://review.whamcloud.com/33005
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Jian Yu <yujian@whamcloud.com>
Reviewed-by: Doug Oucharek <dougso@me.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>