Properly resize paletted bitmaps when adjusting for density

If an app used a GIF file in the wrong density bucket, the auto-scaling
code would not properly resize the bitmap.

This issue affects third party applications, here is the external bug
report:

http://code.google.com/p/android/issues/detail?id=34619

DO NOT MERGE

Change-Id: I7f99b28ad6e6c28bdbcb29bbbadcb215268ff710