plugin code needed some updating because it was interacting badly with
PCH code in pluginhandler::ignoreLocation
Change-Id: I228f94a4e285747bd1d5b8536010f8617118cafa
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/115212
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>