Makefile: sort LIB_H list

This was mostly sorted already, but put things like
"cache-tree.h" after "cache.h", even though "-" comes before
"." (at least in the C locale). This will make it easier to
keep the list sorted later by piping it through "sort".

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -595,8 +595,8 @@ LIB_H += attr.h
 LIB_H += blob.h
 LIB_H += builtin.h
 LIB_H += bulk-checkin.h
-LIB_H += cache.h
 LIB_H += cache-tree.h
+LIB_H += cache.h
 LIB_H += color.h
 LIB_H += commit.h
 LIB_H += compat/bswap.h
@@ -636,13 +636,13 @@ LIB_H += mailmap.h
 LIB_H += merge-file.h
 LIB_H += merge-recursive.h
 LIB_H += mergesort.h
-LIB_H += notes.h
 LIB_H += notes-cache.h
 LIB_H += notes-merge.h
+LIB_H += notes.h
 LIB_H += object.h
-LIB_H += pack.h
 LIB_H += pack-refs.h
 LIB_H += pack-revindex.h
+LIB_H += pack.h
 LIB_H += parse-options.h
 LIB_H += patch-ids.h
 LIB_H += pkt-line.h
@@ -668,8 +668,8 @@ LIB_H += submodule.h
 LIB_H += tag.h
 LIB_H += thread-utils.h
 LIB_H += transport.h
-LIB_H += tree.h
 LIB_H += tree-walk.h
+LIB_H += tree.h
 LIB_H += unpack-trees.h
 LIB_H += userdiff.h
 LIB_H += utf8.h