CA-114341: explicitly use keyword argument

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
CA-114341: don't try to reacquire the lock

Signed-off-by: Thanos Makatos <thanos.makatos@citrix.com>
Reviewed-by: Germano Percossi <germano.percossi@citrix.com>
Merge CA-114341

Signed-off-by: Germano Percossi <germano.percossi@citrix.com>

Github: closes #97 on xapi-project/sm