Now that str_buf takes care of all the allocations, there is
no more gain to pass an argument count.

So this patch removes the "count" argument from:
	- "sq_quote_argv"
	- "trace_argv_printf"
and all the callers.
Signed-off-by: NChristian Couder <chriscool@tuxfamily.org>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>