to pick up things without extensions, for consistency with file->open

Change-Id: Ib119fb0d053d1d288eee7cd17fa4f12dcb9956d7
Reviewed-on: https://gerrit.libreoffice.org/73276
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>