ui/curses: Fix color attribute of monitor for curses

Current text_console_update() writes totally broken color attributes
to console_write_ch(). The format now is writing,

[WRONG]
	bold << 21 | fg << 12 | bg << 8 | char
	fg == 3bits curses color number
	bg == 3bits curses color number

I can't see this format is where come from. Anyway, this doesn't work
at all.

What curses expects is actually (and vga.c is using),

[RIGHT]
	bold << 21 | bg << 11 | fg << 8 | char
	fg == 3bits vga color number
	bg == 3bits vga color number

And curses set COLOR_PAIR() up to match this format, and curses's
chtype. I.e,

	bold | color_pair | char
	color_pair == (bg << 3 | fg)

To fix, this simply uses VGA color number everywhere except curses.c
internal. Then, convert it to above [RIGHT] format to write by
console_write_ch(). And as bonus, this reduces to expose curses define
to other parts (removes COLOR_* from console.c).

[Tested the first line is displayed as white on blue back for monitor
in curses console]

Signed-off-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Message-id: 87r3j95407.fsf@mail.parknet.co.jp
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>