depend-cleanup.sh: Fix overzealous rescue.mk cleanup

grep -q -v means "are there any lines that don't match", not "are there
no lines that match", and since the file has lines other than ones with
nvme_util.o when up-to-date this triggers on every build.

Fixes: 26a09db3add3 ("Fix incremental build with WITH_NVME newly enabled")
MFC after: 1 week