git-compat-util: make UNLEAK less error-prone

git-compat-util: make UNLEAK less error-prone

Commit 0e5bba5 ("add UNLEAK annotation for reducing leak false
positives", 2017-09-08) introduced an UNLEAK macro to be used as
"UNLEAK(var);", but its existing definitions leave semicolons that act
as empty statements, which will lead to syntax errors, e.g.

	if (condition)
		UNLEAK(var);
	else
		something_else(var);

would be broken with two statements between if (condition) and else.
Lose the excess semicolon from the end of the macro replacement text.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>