code since no Win32 device names are used anymore.
* fhandler_tape.cc (fhandler_dev_tape::tape_set_blocksize): Allow
0 as blocksize to indicate variable blocksize.
* path.cc (win32_device_name): Generate NT internal device names
using upper/lower case names for readability.
Generate \DosDevices\<letter>: device name for mount table
compatibility devices.