Merge branch 'jc/maint-1.6.0-keep-pack' into maint

* jc/maint-1.6.0-keep-pack:
  pack-objects: don't loosen objects available in alternate or kept packs
  t7700: demonstrate repack flaw which may loosen objects unnecessarily
  Remove --kept-pack-only option and associated infrastructure
  pack-objects: only repack or loosen objects residing in "local" packs
  git-repack.sh: don't use --kept-pack-only option to pack-objects
  t7700-repack: add two new tests demonstrating repacking flaws
  is_kept_pack(): final clean-up
  Simplify is_kept_pack()
  Consolidate ignore_packed logic more
  has_sha1_kept_pack(): take "struct rev_info"
  has_sha1_pack(): refactor "pretend these packs do not exist" interface
  git-repack: resist stray environment variable

Conflicts:
	t/t7700-repack.sh

git-repack.sh

@@ -60,6 +60,7 @@ case ",$all_into_one," in
 	args='--unpacked --incremental'
 	;;
 ,t,)
+	args= existing=
 	if [ -d "$PACKDIR" ]; then
 		for e in `cd "$PACKDIR" && find . -type f -name '*.pack' \
 			| sed -e 's/^\.\///' -e 's/\.pack$//'`
@@ -67,11 +68,10 @@ case ",$all_into_one," in
 			if [ -e "$PACKDIR/$e.keep" ]; then
 				: keep
 			else
-				args="$args --unpacked=$e.pack"
 				existing="$existing $e"
 			fi
 		done
-		if test -n "$args" -a -n "$unpack_unreachable" -a \
+		if test -n "$existing" -a -n "$unpack_unreachable" -a \
 			-n "$remove_redundant"
 		then
 			args="$args $unpack_unreachable"