by avoiding taking the mutex

Also reduce the code that the mutex covers to the minimum necessary.

Change-Id: I115c8a447ec17f4800c39557e8de0bc8c669b47b
Reviewed-on: https://gerrit.libreoffice.org/62936Reviewed-by: Michael Meeks <michael.meeks@collabora.com>
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>