Remove spaces from CTL devices' default serial numbers

[asomers]

Summary

Remove spaces from CTL devices' default serial numbers

It's awkward to have spaces in CAM device serial numbers. That leads to
such things as device nodes named "/dev/diskid/MYSERIAL%20%20%201". Better
to replace the spaces with "0"s. This change only affects the default
serial numbers for users who don't provide their own.

[ken]

Looks good to me, thanks!

[mav]

I have no objections against the change. Though the whole concept of using so simple and repeatable LUN IDs is a request for troubles caused by conflicts.