When 'tpatch' was initialized successfully, st_mode was already taken
from the previous diff. We should not try to override it with data
from an lstat() that was never called.
This is a companion patch to 7a07841(git-apply: handle a patch that
touches the same path more than once better).
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>