object.h: add flags allocated by pack-bitmap.h

In commit 7cc8f97 (pack-objects: implement bitmap writing,
2013-12-21) the NEEDS_BITMAP flag was introduced into pack-bitmap.h, but
no object flags allocation table existed at the time.

In 208acbf (object.h: centralize object flag allocation, 2014-03-25)
when that table was first introduced, we never added the flags from
7cc8f97, which has remained the case since.

Rectify this by including the flag bit used by pack-bitmap.h into the
centralized table in object.h.

Signed-off-by: Taylor Blau <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: ttaylorr

object.h

@@ -81,6 +81,7 @@ void object_array_init(struct object_array *array);
  * reflog.c:                           10--12
  * builtin/show-branch.c:    0-------------------------------------------26
  * builtin/unpack-objects.c:                                 2021
+ * pack-bitmap.h:                                                22
  */
 #define FLAG_BITS  28