Makefile: use overridable $(FIND) instead of hard-coded 'find'
Makefile: use overridable $(FIND) instead of hard-coded 'find'

The Makefile already offers the variable $(FIND) and uses it except in one
place. Fix it.

Signed-off-by: Johannes Sixt <fd432345609ae4d58c1aa629cb66ba96d1391622@kdbg.org>
Signed-off-by: Junio C Hamano <a6723cc3f76163bf7adb636a73ac3b0ceb3e6b9b@pobox.com>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git