[lltx] mkluatexfontdb tracing

[Will Robertson]

Hi,

When I run mkluatexfontdb, I get output that looks like this:

luaotfload | scanning TEXMF fonts:
[=============================================================================>]
luaotfload | scanning OS fonts:
[======================================>                                       ]
luaotfload | error: failed to open /Library/Fonts/NISC18030.ttf
[=========================================================>                    ]
luaotfload | ignoring font '/System/Library/Fonts/LastResort.ttf'
[=============================================================================>]
luaotfload | 619 fonts in the database


I think we probably want to suppress those two info lines, as they're generally not useful to most people. (As neither of these are fonts that anyone is going to want to load.)

I've changed the script to have these conditional to trace_progress.

-- Will