When passing LUN IDs through treat ASCII values as fixed-length, not
interpreting NULLs as EOLs, but converting them to spaces.

SPC-4 does not tell that T10-based IDs should be NULL-terminated/padded.
And while it tells that it should include only ASCII chars (0x20-0x7F),
there are some USB sticks (SanDisk Ultra Fit), that have NULLs inside
the value.  Treating NULLs as EOLs there made those LUN IDs non-unique.

Ticket:	#6857
Ticket:	#6842

(cherry picked from commit d99dad80f5a85492f757ab60d5e2b5ba1e33bb29)