LU-13002 tests: change clean up in sanity-lnet

LU-13002 tests: change clean up in sanity-lnet

sanity-lnet should detect the state of the system before executing,
and restore that state when it has finished.

Test-Parameters: trivial
Test-Parameters: testlist=sanity-lnet,runtests
Signed-off-by: James Nunez <jnunez@whamcloud.com>
Change-Id: I3e3c5465789389e840efab516b35234cd61be901
Reviewed-on: https://review.whamcloud.com/36849
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Chris Horn <hornc@cray.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>