vcl: warning C4717: GetCharCount() recursive on all control paths

Change-Id: Id86dcd2c701510ce15cc2cf71e35c1d908ec6049
svx: fix another temp file leak, from SdrMediaObj's glTF models

These need a whole directory, apparently a model may have multiple
files.

Change-Id: I092c1764ddb1ed30947034f299fbb6882658d21b