LU-13082 tests: enable lgss_keyring debug traces

LU-13082 tests: enable lgss_keyring debug traces

Enable lgss_keyring debug traces in test framework, and collect
systemd journal in case of test failure.
Also, if needed, dump SSK keys, keyring and nodemap definitions.

Test-Parameters: trivial
Test-Parameters: envdefinitions=SHARED_KEY=true testlist=sanity
Signed-off-by: Sebastien Buisson <sbuisson@ddn.com>
Change-Id: I201d97b640045e3cbc8dcd4cd4b25e0e4e644037
Reviewed-on: https://review.whamcloud.com/37042
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Nunez <jnunez@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>