git-compat-util.h: drop trailing semicolon from macro definition

git-compat-util.h: drop trailing semicolon from macro definition

Make CALLOC_ARRAY usable like a function by requiring callers to supply
the trailing semicolon, which all of the current ones already do.  With
the extra semicolon e.g. the following code wouldn't compile because it
disconnects the "else" from the "if":

	if (condition)
		CALLOC_ARRAY(ptr, n);
	else
		whatever();

Signed-off-by: René Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>