Merge branch 'md/list-lazy-objects-fix'

"git rev-list --exclude-promisor-objects" had to take an object
that does not exist locally (and is lazily available) from the
command line without barfing, but the code dereferenced NULL.

* md/list-lazy-objects-fix:
list-objects.c: don't segfault for missing cmdline objects

diff --cc revision.c
Simple merge

diff --cc t/t0410-partial-clone.sh
Simple merge