Move pGlobalShell into properties container

Change-Id: I10eca8c422f8242a892a0c6608a874ed8a37dd46
Reviewed-on: https://gerrit.libreoffice.org/12482
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>