Revert "move pack creation to version 3"

This reverts commit 16854571aa.
Git as recent as v1.1.6 do not understand version 3 delta.

v1.2.0 is Ok and I personally would say it is old enough, but
the improvement between version 2 and version 3 delta is not
bit enough to justify breaking older clients.

We should resurrect this later, but when we do so we shold
make it conditional.

Signed-off-by: Junio C Hamano <junkio@cox.net>

diff-delta.c

@@ -308,8 +308,8 @@ create_delta(const struct delta_index *index,
 				continue;
 			if (ref_size > top - src)
 				ref_size = top - src;
-			if (ref_size > 0xffffff)
-				ref_size = 0xffffff;
+			if (ref_size > 0x10000)
+				ref_size = 0x10000;
 			if (ref_size <= msize)
 				break;
 			while (ref_size-- && *src++ == *ref)
@@ -318,8 +318,6 @@ create_delta(const struct delta_index *index,
 				/* this is our best match so far */
 				msize = ref - entry->ptr;
 				moff = entry->ptr - ref_data;
-				if (msize >= 0x10000)
-					break;  /* this is good enough */
 			}
 		}
 
@@ -383,8 +381,6 @@ create_delta(const struct delta_index *index,
 			if (msize & 0xff) { out[outpos++] = msize; i |= 0x10; }
 			msize >>= 8;
 			if (msize & 0xff) { out[outpos++] = msize; i |= 0x20; }
-			msize >>= 8;
-			if (msize & 0xff) { out[outpos++] = msize; i |= 0x40; }
 
 			*op = i;
 		}

pack.h

@@ -7,7 +7,7 @@
  * Packed object header
  */
 #define PACK_SIGNATURE 0x5041434b	/* "PACK" */
-#define PACK_VERSION 3
+#define PACK_VERSION 2
 #define pack_version_ok(v) ((v) == htonl(2) || (v) == htonl(3))
 struct pack_header {
 	unsigned int hdr_signature;