LU-8021 tests: In interop, ensure to save/restore correct debug flags

LU-8021 tests: In interop, ensure to save/restore correct debug flags

debugsave() and debugrestore() in test-framework.sh save the
same debug flags of the client on servers as well.

In case of interop, esp between lustre 2.1.x server and
2.5.x clients, with PTLDEBUG=-1 the debugrestore() would fail as
there are some flags which are newly added to 2.5.x,
    e.g. "lfsck, hsm" are not defined on 2.1.x servers.

- The fix, makes sure to save the debug flags for servers and clients
separately and thus restore correctly.

- It restores the debug flags irrespective of, if the server node
is active or passive, failover node.

- It takes care,
	if any of the node(server OR client) is down or unreachable,
	if there are separate MDS MGS servers,
	if any of the node is rebooted (FAILURE_MODE=hard)
	but lustre modules are not loaded.

Also, there is defect introduced by LU-4480 in reset_fail_loc,
this patch fixes that as well.

Seagate-bug-id: MRP-1959
Change-Id: I6c6142cc113f8131bb89e6dc313215440f2242b9
Signed-off-by: Parinay Kondekar <parinay.kondekar@seagate.com>
Reviewed-by: Elena Gryaznova <elena.gryaznova@seagate.com>
Reviewed-by: Ujjwal Lanjewar <ujjwal.lanjewar@seagate.com>
Reviewed-on: http://review.whamcloud.com/19604
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>