since we only use the AsciiCString enumerator.
Consequently simplify the GetConnectionIdentifier method

Change-Id: I9e1a1318d2f12bfd18edeb8479e0e7171b22d0f1
Reviewed-on: https://gerrit.libreoffice.org/34026Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Noel Grandin <noel.grandin@collabora.co.uk>